diff --git a/spine-cpp/tests/SkeletonSerializer.h b/spine-cpp/tests/SkeletonSerializer.h
index 9ccf71a35..5dfc539bb 100644
--- a/spine-cpp/tests/SkeletonSerializer.h
+++ b/spine-cpp/tests/SkeletonSerializer.h
@@ -10,7 +10,8 @@ namespace spine {
 
 	class SkeletonSerializer {
 	private:
-		HashMap<void *, bool> _visitedObjects;
+		HashMap<void *, String> _visitedObjects;
+		int _nextId;
 		JsonWriter _json;
 
 	public:
@@ -21,6 +22,7 @@ namespace spine {
 
 		String serializeSkeletonData(SkeletonData *data) {
 			_visitedObjects.clear();
+			_nextId = 1;
 			_json = JsonWriter();
 			writeSkeletonData(data);
 			return _json.getString();
@@ -28,6 +30,7 @@ namespace spine {
 
 		String serializeSkeleton(Skeleton *skeleton) {
 			_visitedObjects.clear();
+			_nextId = 1;
 			_json = JsonWriter();
 			writeSkeleton(skeleton);
 			return _json.getString();
@@ -35,6 +38,7 @@ namespace spine {
 
 		String serializeAnimationState(AnimationState *state) {
 			_visitedObjects.clear();
+			_nextId = 1;
 			_json = JsonWriter();
 			writeAnimationState(state);
 			return _json.getString();
@@ -43,12 +47,21 @@ namespace spine {
 	private:
 		void writeAnimation(Animation *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<Animation-").append(name).append(">");
+			} else {
+				refString.append("<Animation-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("Animation");
 
@@ -73,12 +86,15 @@ namespace spine {
 
 		void writeAlphaTimeline(AlphaTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<AlphaTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("AlphaTimeline");
 
@@ -113,12 +129,15 @@ namespace spine {
 
 		void writeAttachmentTimeline(AttachmentTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<AttachmentTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("AttachmentTimeline");
 
@@ -160,12 +179,15 @@ namespace spine {
 
 		void writeDeformTimeline(DeformTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<DeformTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("DeformTimeline");
 
@@ -215,12 +237,15 @@ namespace spine {
 
 		void writeDrawOrderTimeline(DrawOrderTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<DrawOrderTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("DrawOrderTimeline");
 
@@ -264,12 +289,15 @@ namespace spine {
 
 		void writeEventTimeline(EventTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<EventTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("EventTimeline");
 
@@ -308,12 +336,15 @@ namespace spine {
 
 		void writeIkConstraintTimeline(IkConstraintTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<IkConstraintTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("IkConstraintTimeline");
 
@@ -348,12 +379,15 @@ namespace spine {
 
 		void writeInheritTimeline(InheritTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<InheritTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("InheritTimeline");
 
@@ -388,12 +422,15 @@ namespace spine {
 
 		void writePathConstraintMixTimeline(PathConstraintMixTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PathConstraintMixTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PathConstraintMixTimeline");
 
@@ -428,12 +465,15 @@ namespace spine {
 
 		void writePathConstraintPositionTimeline(PathConstraintPositionTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PathConstraintPositionTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PathConstraintPositionTimeline");
 
@@ -468,12 +508,15 @@ namespace spine {
 
 		void writePathConstraintSpacingTimeline(PathConstraintSpacingTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PathConstraintSpacingTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PathConstraintSpacingTimeline");
 
@@ -508,12 +551,15 @@ namespace spine {
 
 		void writePhysicsConstraintDampingTimeline(PhysicsConstraintDampingTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraintDampingTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintDampingTimeline");
 
@@ -548,12 +594,15 @@ namespace spine {
 
 		void writePhysicsConstraintGravityTimeline(PhysicsConstraintGravityTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraintGravityTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintGravityTimeline");
 
@@ -588,12 +637,15 @@ namespace spine {
 
 		void writePhysicsConstraintInertiaTimeline(PhysicsConstraintInertiaTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraintInertiaTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintInertiaTimeline");
 
@@ -628,12 +680,15 @@ namespace spine {
 
 		void writePhysicsConstraintMassTimeline(PhysicsConstraintMassTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraintMassTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintMassTimeline");
 
@@ -668,12 +723,15 @@ namespace spine {
 
 		void writePhysicsConstraintMixTimeline(PhysicsConstraintMixTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraintMixTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintMixTimeline");
 
@@ -708,12 +766,15 @@ namespace spine {
 
 		void writePhysicsConstraintResetTimeline(PhysicsConstraintResetTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraintResetTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintResetTimeline");
 
@@ -748,12 +809,15 @@ namespace spine {
 
 		void writePhysicsConstraintStrengthTimeline(PhysicsConstraintStrengthTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraintStrengthTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintStrengthTimeline");
 
@@ -788,12 +852,15 @@ namespace spine {
 
 		void writePhysicsConstraintWindTimeline(PhysicsConstraintWindTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraintWindTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintWindTimeline");
 
@@ -828,12 +895,15 @@ namespace spine {
 
 		void writeRGB2Timeline(RGB2Timeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<RGB2Timeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("RGB2Timeline");
 
@@ -868,12 +938,15 @@ namespace spine {
 
 		void writeRGBA2Timeline(RGBA2Timeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<RGBA2Timeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("RGBA2Timeline");
 
@@ -908,12 +981,15 @@ namespace spine {
 
 		void writeRGBATimeline(RGBATimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<RGBATimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("RGBATimeline");
 
@@ -948,12 +1024,15 @@ namespace spine {
 
 		void writeRGBTimeline(RGBTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<RGBTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("RGBTimeline");
 
@@ -988,12 +1067,15 @@ namespace spine {
 
 		void writeRotateTimeline(RotateTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<RotateTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("RotateTimeline");
 
@@ -1028,12 +1110,15 @@ namespace spine {
 
 		void writeScaleTimeline(ScaleTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ScaleTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ScaleTimeline");
 
@@ -1068,12 +1153,15 @@ namespace spine {
 
 		void writeScaleXTimeline(ScaleXTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ScaleXTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ScaleXTimeline");
 
@@ -1108,12 +1196,15 @@ namespace spine {
 
 		void writeScaleYTimeline(ScaleYTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ScaleYTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ScaleYTimeline");
 
@@ -1148,12 +1239,15 @@ namespace spine {
 
 		void writeSequenceTimeline(SequenceTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<SequenceTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("SequenceTimeline");
 
@@ -1191,12 +1285,15 @@ namespace spine {
 
 		void writeShearTimeline(ShearTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ShearTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ShearTimeline");
 
@@ -1231,12 +1328,15 @@ namespace spine {
 
 		void writeShearXTimeline(ShearXTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ShearXTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ShearXTimeline");
 
@@ -1271,12 +1371,15 @@ namespace spine {
 
 		void writeShearYTimeline(ShearYTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ShearYTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ShearYTimeline");
 
@@ -1311,12 +1414,15 @@ namespace spine {
 
 		void writeSliderMixTimeline(SliderMixTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<SliderMixTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("SliderMixTimeline");
 
@@ -1351,12 +1457,15 @@ namespace spine {
 
 		void writeSliderTimeline(SliderTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<SliderTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("SliderTimeline");
 
@@ -1470,12 +1579,15 @@ namespace spine {
 
 		void writeTransformConstraintTimeline(TransformConstraintTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<TransformConstraintTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("TransformConstraintTimeline");
 
@@ -1510,12 +1622,15 @@ namespace spine {
 
 		void writeTranslateTimeline(TranslateTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<TranslateTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("TranslateTimeline");
 
@@ -1550,12 +1665,15 @@ namespace spine {
 
 		void writeTranslateXTimeline(TranslateXTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<TranslateXTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("TranslateXTimeline");
 
@@ -1590,12 +1708,15 @@ namespace spine {
 
 		void writeTranslateYTimeline(TranslateYTimeline *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<TranslateYTimeline-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("TranslateYTimeline");
 
@@ -1630,12 +1751,15 @@ namespace spine {
 
 		void writeAnimationState(AnimationState *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<AnimationState-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("AnimationState");
 
@@ -1657,12 +1781,15 @@ namespace spine {
 
 		void writeTrackEntry(TrackEntry *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<TrackEntry-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("TrackEntry");
 
@@ -1781,12 +1908,15 @@ namespace spine {
 
 		void writeAnimationStateData(AnimationStateData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<AnimationStateData-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("AnimationStateData");
 
@@ -1820,12 +1950,15 @@ namespace spine {
 
 		void writeBone(Bone *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<Bone-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("Bone");
 
@@ -1857,12 +1990,21 @@ namespace spine {
 
 		void writeBoneData(BoneData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<BoneData-").append(name).append(">");
+			} else {
+				refString.append("<BoneData-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("BoneData");
 
@@ -1902,12 +2044,15 @@ namespace spine {
 
 		void writeBoneLocal(BoneLocal *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<BoneLocal-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("BoneLocal");
 
@@ -1955,12 +2100,15 @@ namespace spine {
 
 		void writeBonePose(BonePose *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<BonePose-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("BonePose");
 
@@ -2038,12 +2186,21 @@ namespace spine {
 
 		void writeBoundingBoxAttachment(BoundingBoxAttachment *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<BoundingBoxAttachment-").append(name).append(">");
+			} else {
+				refString.append("<BoundingBoxAttachment-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("BoundingBoxAttachment");
 
@@ -2085,12 +2242,21 @@ namespace spine {
 
 		void writeClippingAttachment(ClippingAttachment *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<ClippingAttachment-").append(name).append(">");
+			} else {
+				refString.append("<ClippingAttachment-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ClippingAttachment");
 
@@ -2173,12 +2339,15 @@ namespace spine {
 
 		void writeEvent(Event *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<Event-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("Event");
 
@@ -2208,12 +2377,21 @@ namespace spine {
 
 		void writeEventData(EventData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<EventData-").append(name).append(">");
+			} else {
+				refString.append("<EventData-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("EventData");
 
@@ -2243,12 +2421,15 @@ namespace spine {
 
 		void writeIkConstraint(IkConstraint *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<IkConstraint-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("IkConstraint");
 
@@ -2276,12 +2457,21 @@ namespace spine {
 
 		void writeIkConstraintData(IkConstraintData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<IkConstraintData-").append(name).append(">");
+			} else {
+				refString.append("<IkConstraintData-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("IkConstraintData");
 
@@ -2312,12 +2502,15 @@ namespace spine {
 
 		void writeIkConstraintPose(IkConstraintPose *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<IkConstraintPose-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("IkConstraintPose");
 
@@ -2341,12 +2534,21 @@ namespace spine {
 
 		void writeMeshAttachment(MeshAttachment *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<MeshAttachment-").append(name).append(">");
+			} else {
+				refString.append("<MeshAttachment-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("MeshAttachment");
 
@@ -2449,12 +2651,21 @@ namespace spine {
 
 		void writePathAttachment(PathAttachment *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<PathAttachment-").append(name).append(">");
+			} else {
+				refString.append("<PathAttachment-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PathAttachment");
 
@@ -2509,12 +2720,15 @@ namespace spine {
 
 		void writePathConstraint(PathConstraint *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PathConstraint-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PathConstraint");
 
@@ -2542,12 +2756,21 @@ namespace spine {
 
 		void writePathConstraintData(PathConstraintData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<PathConstraintData-").append(name).append(">");
+			} else {
+				refString.append("<PathConstraintData-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PathConstraintData");
 
@@ -2620,12 +2843,15 @@ namespace spine {
 
 		void writePathConstraintPose(PathConstraintPose *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PathConstraintPose-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PathConstraintPose");
 
@@ -2649,12 +2875,15 @@ namespace spine {
 
 		void writePhysicsConstraint(PhysicsConstraint *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraint-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraint");
 
@@ -2675,12 +2904,21 @@ namespace spine {
 
 		void writePhysicsConstraintData(PhysicsConstraintData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<PhysicsConstraintData-").append(name).append(">");
+			} else {
+				refString.append("<PhysicsConstraintData-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintData");
 
@@ -2743,12 +2981,15 @@ namespace spine {
 
 		void writePhysicsConstraintPose(PhysicsConstraintPose *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<PhysicsConstraintPose-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PhysicsConstraintPose");
 
@@ -2778,12 +3019,21 @@ namespace spine {
 
 		void writePointAttachment(PointAttachment *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<PointAttachment-").append(name).append(">");
+			} else {
+				refString.append("<PointAttachment-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("PointAttachment");
 
@@ -2807,12 +3057,21 @@ namespace spine {
 
 		void writeRegionAttachment(RegionAttachment *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<RegionAttachment-").append(name).append(">");
+			} else {
+				refString.append("<RegionAttachment-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("RegionAttachment");
 
@@ -2879,12 +3138,15 @@ namespace spine {
 
 		void writeSequence(Sequence *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<Sequence-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("Sequence");
 
@@ -2912,12 +3174,15 @@ namespace spine {
 
 		void writeSkeleton(Skeleton *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<Skeleton-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("Skeleton");
 
@@ -3011,12 +3276,21 @@ namespace spine {
 
 		void writeSkeletonData(SkeletonData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<SkeletonData-").append(name).append(">");
+			} else {
+				refString.append("<SkeletonData-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("SkeletonData");
 
@@ -3107,12 +3381,22 @@ namespace spine {
 
 		void writeSkin(Skin *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<Skin-").append(name).append(">");
+			} else {
+				refString.append("<Skin-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
+
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("Skin");
 
@@ -3152,6 +3436,15 @@ namespace spine {
 
 		void writeSkinEntry(Skin::AttachmentMap::Entry *obj) {
 			_json.writeObjectStart();
+			String name = obj->_name;
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<SkinEntry-").append(name).append(">");
+			} else {
+				refString.append("<SkinEntry-").append(_nextId++).append(">");
+			}
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("SkinEntry");
 			_json.writeName("slotIndex");
@@ -3165,12 +3458,15 @@ namespace spine {
 
 		void writeSlider(Slider *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<Slider-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("Slider");
 
@@ -3191,12 +3487,21 @@ namespace spine {
 
 		void writeSliderData(SliderData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<SliderData-").append(name).append(">");
+			} else {
+				refString.append("<SliderData-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("SliderData");
 
@@ -3246,12 +3551,15 @@ namespace spine {
 
 		void writeSliderPose(SliderPose *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<SliderPose-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("SliderPose");
 
@@ -3266,12 +3574,15 @@ namespace spine {
 
 		void writeSlot(Slot *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<Slot-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("Slot");
 
@@ -3292,12 +3603,21 @@ namespace spine {
 
 		void writeSlotData(SlotData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<SlotData-").append(name).append(">");
+			} else {
+				refString.append("<SlotData-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("SlotData");
 
@@ -3343,12 +3663,15 @@ namespace spine {
 
 		void writeSlotPose(SlotPose *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<SlotPose-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("SlotPose");
 
@@ -3380,12 +3703,15 @@ namespace spine {
 
 		void writeTransformConstraint(TransformConstraint *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<TransformConstraint-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("TransformConstraint");
 
@@ -3413,12 +3739,21 @@ namespace spine {
 
 		void writeTransformConstraintData(TransformConstraintData *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String name = obj->getName();
+			String refString;
+			if (!name.isEmpty()) {
+				refString.append("<TransformConstraintData-").append(name).append(">");
+			} else {
+				refString.append("<TransformConstraintData-").append(_nextId++).append(">");
+			}
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("TransformConstraintData");
 
@@ -3502,12 +3837,15 @@ namespace spine {
 
 		void writeFromRotate(FromRotate *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<FromRotate-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("FromRotate");
 
@@ -3526,12 +3864,15 @@ namespace spine {
 
 		void writeFromScaleX(FromScaleX *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<FromScaleX-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("FromScaleX");
 
@@ -3550,12 +3891,15 @@ namespace spine {
 
 		void writeFromScaleY(FromScaleY *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<FromScaleY-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("FromScaleY");
 
@@ -3574,12 +3918,15 @@ namespace spine {
 
 		void writeFromShearY(FromShearY *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<FromShearY-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("FromShearY");
 
@@ -3598,12 +3945,15 @@ namespace spine {
 
 		void writeFromX(FromX *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<FromX-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("FromX");
 
@@ -3622,12 +3972,15 @@ namespace spine {
 
 		void writeFromY(FromY *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<FromY-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("FromY");
 
@@ -3665,12 +4018,15 @@ namespace spine {
 
 		void writeToRotate(ToRotate *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ToRotate-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ToRotate");
 
@@ -3688,12 +4044,15 @@ namespace spine {
 
 		void writeToScaleX(ToScaleX *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ToScaleX-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ToScaleX");
 
@@ -3711,12 +4070,15 @@ namespace spine {
 
 		void writeToScaleY(ToScaleY *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ToScaleY-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ToScaleY");
 
@@ -3734,12 +4096,15 @@ namespace spine {
 
 		void writeToShearY(ToShearY *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ToShearY-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ToShearY");
 
@@ -3757,12 +4122,15 @@ namespace spine {
 
 		void writeToX(ToX *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ToX-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ToX");
 
@@ -3780,12 +4148,15 @@ namespace spine {
 
 		void writeToY(ToY *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<ToY-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("ToY");
 
@@ -3803,12 +4174,15 @@ namespace spine {
 
 		void writeTransformConstraintPose(TransformConstraintPose *obj) {
 			if (_visitedObjects.containsKey(obj)) {
-				_json.writeValue("<circular>");
+				_json.writeValue(_visitedObjects[obj]);
 				return;
 			}
-			_visitedObjects.put(obj, true);
+			String refString = String("<TransformConstraintPose-").append(_nextId++).append(">");
+			_visitedObjects.put(obj, refString);
 
 			_json.writeObjectStart();
+			_json.writeName("refString");
+			_json.writeValue(refString);
 			_json.writeName("type");
 			_json.writeValue("TransformConstraintPose");
 
diff --git a/spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/utils/SkeletonSerializer.java b/spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/utils/SkeletonSerializer.java
index 90b9bc51e..a45a7d4c3 100644
--- a/spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/utils/SkeletonSerializer.java
+++ b/spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/utils/SkeletonSerializer.java
@@ -16,15 +16,17 @@ import com.badlogic.gdx.utils.IntArray;
 import com.badlogic.gdx.utils.FloatArray;
 
 import java.util.Locale;
-import java.util.Set;
-import java.util.HashSet;
+import java.util.Map;
+import java.util.HashMap;
 
 public class SkeletonSerializer {
-	private final Set<Object> visitedObjects = new HashSet<>();
+	private final Map<Object, String> visitedObjects = new HashMap<>();
+	private int nextId = 1;
 	private JsonWriter json;
 
 	public String serializeSkeletonData (SkeletonData data) {
 		visitedObjects.clear();
+		nextId = 1;
 		json = new JsonWriter();
 		writeSkeletonData(data);
 		json.close();
@@ -33,6 +35,7 @@ public class SkeletonSerializer {
 
 	public String serializeSkeleton (Skeleton skeleton) {
 		visitedObjects.clear();
+		nextId = 1;
 		json = new JsonWriter();
 		writeSkeleton(skeleton);
 		json.close();
@@ -41,6 +44,7 @@ public class SkeletonSerializer {
 
 	public String serializeAnimationState (AnimationState state) {
 		visitedObjects.clear();
+		nextId = 1;
 		json = new JsonWriter();
 		writeAnimationState(state);
 		json.close();
@@ -48,13 +52,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeAnimation (Animation obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<Animation-" + obj.getName() + ">" : "<Animation-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("Animation");
 
@@ -78,13 +85,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeAlphaTimeline (Animation.AlphaTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<AlphaTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("AlphaTimeline");
 
@@ -118,13 +128,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeAttachmentTimeline (Animation.AttachmentTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<AttachmentTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("AttachmentTimeline");
 
@@ -165,13 +178,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeDeformTimeline (Animation.DeformTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<DeformTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("DeformTimeline");
 
@@ -219,13 +235,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeDrawOrderTimeline (Animation.DrawOrderTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<DrawOrderTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("DrawOrderTimeline");
 
@@ -267,13 +286,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeEventTimeline (Animation.EventTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<EventTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("EventTimeline");
 
@@ -311,13 +333,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeIkConstraintTimeline (Animation.IkConstraintTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<IkConstraintTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("IkConstraintTimeline");
 
@@ -351,13 +376,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeInheritTimeline (Animation.InheritTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<InheritTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("InheritTimeline");
 
@@ -391,13 +419,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePathConstraintMixTimeline (Animation.PathConstraintMixTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PathConstraintMixTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PathConstraintMixTimeline");
 
@@ -431,13 +462,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePathConstraintPositionTimeline (Animation.PathConstraintPositionTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PathConstraintPositionTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PathConstraintPositionTimeline");
 
@@ -471,13 +505,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePathConstraintSpacingTimeline (Animation.PathConstraintSpacingTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PathConstraintSpacingTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PathConstraintSpacingTimeline");
 
@@ -511,13 +548,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintDampingTimeline (Animation.PhysicsConstraintDampingTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraintDampingTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintDampingTimeline");
 
@@ -551,13 +591,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintGravityTimeline (Animation.PhysicsConstraintGravityTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraintGravityTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintGravityTimeline");
 
@@ -591,13 +634,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintInertiaTimeline (Animation.PhysicsConstraintInertiaTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraintInertiaTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintInertiaTimeline");
 
@@ -631,13 +677,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintMassTimeline (Animation.PhysicsConstraintMassTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraintMassTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintMassTimeline");
 
@@ -671,13 +720,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintMixTimeline (Animation.PhysicsConstraintMixTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraintMixTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintMixTimeline");
 
@@ -711,13 +763,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintResetTimeline (Animation.PhysicsConstraintResetTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraintResetTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintResetTimeline");
 
@@ -751,13 +806,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintStrengthTimeline (Animation.PhysicsConstraintStrengthTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraintStrengthTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintStrengthTimeline");
 
@@ -791,13 +849,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintWindTimeline (Animation.PhysicsConstraintWindTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraintWindTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintWindTimeline");
 
@@ -831,13 +892,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeRGB2Timeline (Animation.RGB2Timeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<RGB2Timeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("RGB2Timeline");
 
@@ -871,13 +935,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeRGBA2Timeline (Animation.RGBA2Timeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<RGBA2Timeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("RGBA2Timeline");
 
@@ -911,13 +978,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeRGBATimeline (Animation.RGBATimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<RGBATimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("RGBATimeline");
 
@@ -951,13 +1021,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeRGBTimeline (Animation.RGBTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<RGBTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("RGBTimeline");
 
@@ -991,13 +1064,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeRotateTimeline (Animation.RotateTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<RotateTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("RotateTimeline");
 
@@ -1031,13 +1107,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeScaleTimeline (Animation.ScaleTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ScaleTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ScaleTimeline");
 
@@ -1071,13 +1150,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeScaleXTimeline (Animation.ScaleXTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ScaleXTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ScaleXTimeline");
 
@@ -1111,13 +1193,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeScaleYTimeline (Animation.ScaleYTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ScaleYTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ScaleYTimeline");
 
@@ -1151,13 +1236,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSequenceTimeline (Animation.SequenceTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<SequenceTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("SequenceTimeline");
 
@@ -1194,13 +1282,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeShearTimeline (Animation.ShearTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ShearTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ShearTimeline");
 
@@ -1234,13 +1325,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeShearXTimeline (Animation.ShearXTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ShearXTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ShearXTimeline");
 
@@ -1274,13 +1368,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeShearYTimeline (Animation.ShearYTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ShearYTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ShearYTimeline");
 
@@ -1314,13 +1411,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSliderMixTimeline (Animation.SliderMixTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<SliderMixTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("SliderMixTimeline");
 
@@ -1354,13 +1454,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSliderTimeline (Animation.SliderTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<SliderTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("SliderTimeline");
 
@@ -1472,13 +1575,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeTransformConstraintTimeline (Animation.TransformConstraintTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<TransformConstraintTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("TransformConstraintTimeline");
 
@@ -1512,13 +1618,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeTranslateTimeline (Animation.TranslateTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<TranslateTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("TranslateTimeline");
 
@@ -1552,13 +1661,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeTranslateXTimeline (Animation.TranslateXTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<TranslateXTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("TranslateXTimeline");
 
@@ -1592,13 +1704,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeTranslateYTimeline (Animation.TranslateYTimeline obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<TranslateYTimeline-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("TranslateYTimeline");
 
@@ -1632,13 +1747,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeAnimationState (AnimationState obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<AnimationState-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("AnimationState");
 
@@ -1659,13 +1777,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeTrackEntry (AnimationState.TrackEntry obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<TrackEntry-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("TrackEntry");
 
@@ -1770,13 +1891,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeAnimationStateData (AnimationStateData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<AnimationStateData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("AnimationStateData");
 
@@ -1808,13 +1932,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeBone (Bone obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<Bone-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("Bone");
 
@@ -1845,13 +1972,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeBoneData (BoneData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<BoneData-" + obj.getName() + ">" : "<BoneData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("BoneData");
 
@@ -1890,13 +2020,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeBoneLocal (BoneLocal obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<BoneLocal-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("BoneLocal");
 
@@ -1928,13 +2061,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeBonePose (BonePose obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<BonePose-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("BonePose");
 
@@ -1996,13 +2132,17 @@ public class SkeletonSerializer {
 	}
 
 	private void writeBoundingBoxAttachment (BoundingBoxAttachment obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<BoundingBoxAttachment-" + obj.getName() + ">"
+			: "<BoundingBoxAttachment-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("BoundingBoxAttachment");
 
@@ -2047,13 +2187,17 @@ public class SkeletonSerializer {
 	}
 
 	private void writeClippingAttachment (ClippingAttachment obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<ClippingAttachment-" + obj.getName() + ">"
+			: "<ClippingAttachment-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ClippingAttachment");
 
@@ -2137,13 +2281,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeEvent (Event obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<Event-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("Event");
 
@@ -2172,13 +2319,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeEventData (EventData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<EventData-" + obj.getName() + ">" : "<EventData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("EventData");
 
@@ -2207,13 +2357,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeIkConstraint (IkConstraint obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<IkConstraint-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("IkConstraint");
 
@@ -2240,13 +2393,17 @@ public class SkeletonSerializer {
 	}
 
 	private void writeIkConstraintData (IkConstraintData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<IkConstraintData-" + obj.getName() + ">"
+			: "<IkConstraintData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("IkConstraintData");
 
@@ -2276,13 +2433,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeIkConstraintPose (IkConstraintPose obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<IkConstraintPose-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("IkConstraintPose");
 
@@ -2305,13 +2465,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeMeshAttachment (MeshAttachment obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<MeshAttachment-" + obj.getName() + ">" : "<MeshAttachment-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("MeshAttachment");
 
@@ -2421,13 +2584,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePathAttachment (PathAttachment obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<PathAttachment-" + obj.getName() + ">" : "<PathAttachment-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PathAttachment");
 
@@ -2485,13 +2651,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePathConstraint (PathConstraint obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PathConstraint-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PathConstraint");
 
@@ -2518,13 +2687,17 @@ public class SkeletonSerializer {
 	}
 
 	private void writePathConstraintData (PathConstraintData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<PathConstraintData-" + obj.getName() + ">"
+			: "<PathConstraintData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PathConstraintData");
 
@@ -2563,13 +2736,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePathConstraintPose (PathConstraintPose obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PathConstraintPose-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PathConstraintPose");
 
@@ -2592,13 +2768,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraint (PhysicsConstraint obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraint-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraint");
 
@@ -2618,13 +2797,17 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintData (PhysicsConstraintData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<PhysicsConstraintData-" + obj.getName() + ">"
+			: "<PhysicsConstraintData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintData");
 
@@ -2686,13 +2869,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writePhysicsConstraintPose (PhysicsConstraintPose obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<PhysicsConstraintPose-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PhysicsConstraintPose");
 
@@ -2721,13 +2907,17 @@ public class SkeletonSerializer {
 	}
 
 	private void writePointAttachment (PointAttachment obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<PointAttachment-" + obj.getName() + ">"
+			: "<PointAttachment-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("PointAttachment");
 
@@ -2750,13 +2940,17 @@ public class SkeletonSerializer {
 	}
 
 	private void writeRegionAttachment (RegionAttachment obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<RegionAttachment-" + obj.getName() + ">"
+			: "<RegionAttachment-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("RegionAttachment");
 
@@ -2822,13 +3016,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSequence (Sequence obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<Sequence-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("Sequence");
 
@@ -2855,13 +3052,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSkeleton (Skeleton obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<Skeleton-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("Skeleton");
 
@@ -2954,13 +3154,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSkeletonData (SkeletonData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<SkeletonData-" + obj.getName() + ">" : "<SkeletonData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("SkeletonData");
 
@@ -3050,13 +3253,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSkin (Skin obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<Skin-" + obj.getName() + ">" : "<Skin-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("Skin");
 
@@ -3093,13 +3299,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSkinEntry (Skin.SkinEntry obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<SkinEntry-" + obj.getName() + ">" : "<SkinEntry-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("SkinEntry");
 
@@ -3116,13 +3325,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSlider (Slider obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<Slider-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("Slider");
 
@@ -3142,13 +3354,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSliderData (SliderData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<SliderData-" + obj.getName() + ">" : "<SliderData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("SliderData");
 
@@ -3197,13 +3412,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSliderPose (SliderPose obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<SliderPose-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("SliderPose");
 
@@ -3217,13 +3435,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSlot (Slot obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<Slot-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("Slot");
 
@@ -3243,13 +3464,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSlotData (SlotData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<SlotData-" + obj.getName() + ">" : "<SlotData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("SlotData");
 
@@ -3281,13 +3505,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeSlotPose (SlotPose obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<SlotPose-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("SlotPose");
 
@@ -3318,13 +3545,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeTransformConstraint (TransformConstraint obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<TransformConstraint-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("TransformConstraint");
 
@@ -3351,13 +3581,17 @@ public class SkeletonSerializer {
 	}
 
 	private void writeTransformConstraintData (TransformConstraintData obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = obj.getName() != null ? "<TransformConstraintData-" + obj.getName() + ">"
+			: "<TransformConstraintData-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("TransformConstraintData");
 
@@ -3439,13 +3673,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeFromRotate (TransformConstraintData.FromRotate obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<FromRotate-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("FromRotate");
 
@@ -3463,13 +3700,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeFromScaleX (TransformConstraintData.FromScaleX obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<FromScaleX-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("FromScaleX");
 
@@ -3487,13 +3727,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeFromScaleY (TransformConstraintData.FromScaleY obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<FromScaleY-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("FromScaleY");
 
@@ -3511,13 +3754,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeFromShearY (TransformConstraintData.FromShearY obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<FromShearY-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("FromShearY");
 
@@ -3535,13 +3781,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeFromX (TransformConstraintData.FromX obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<FromX-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("FromX");
 
@@ -3559,13 +3808,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeFromY (TransformConstraintData.FromY obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<FromY-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("FromY");
 
@@ -3601,13 +3853,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeToRotate (TransformConstraintData.ToRotate obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ToRotate-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ToRotate");
 
@@ -3624,13 +3879,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeToScaleX (TransformConstraintData.ToScaleX obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ToScaleX-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ToScaleX");
 
@@ -3647,13 +3905,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeToScaleY (TransformConstraintData.ToScaleY obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ToScaleY-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ToScaleY");
 
@@ -3670,13 +3931,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeToShearY (TransformConstraintData.ToShearY obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ToShearY-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ToShearY");
 
@@ -3693,13 +3957,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeToX (TransformConstraintData.ToX obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ToX-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ToX");
 
@@ -3716,13 +3983,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeToY (TransformConstraintData.ToY obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<ToY-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("ToY");
 
@@ -3739,13 +4009,16 @@ public class SkeletonSerializer {
 	}
 
 	private void writeTransformConstraintPose (TransformConstraintPose obj) {
-		if (visitedObjects.contains(obj)) {
-			json.writeValue("<circular>");
+		if (visitedObjects.containsKey(obj)) {
+			json.writeValue(visitedObjects.get(obj));
 			return;
 		}
-		visitedObjects.add(obj);
+		String refString = "<TransformConstraintPose-" + (nextId++) + ">";
+		visitedObjects.put(obj, refString);
 
 		json.writeObjectStart();
+		json.writeName("refString");
+		json.writeValue(refString);
 		json.writeName("type");
 		json.writeValue("TransformConstraintPose");
 
diff --git a/tests/src/generate-cpp-serializer.ts b/tests/src/generate-cpp-serializer.ts
index fc0789417..7fee064e8 100644
--- a/tests/src/generate-cpp-serializer.ts
+++ b/tests/src/generate-cpp-serializer.ts
@@ -78,7 +78,7 @@ function generatePropertyCode (property: Property, indent: string, enumMappings:
 			}
 			break;
 
-		case "enum":
+		case "enum": {
 			const enumName = property.enumName;
 			const enumMap = enumMappings[enumName];
 
@@ -99,8 +99,8 @@ function generatePropertyCode (property: Property, indent: string, enumMappings:
 				lines.push(`${indent}_json.writeValue(String::valueOf((int)${accessor}));`);
 			}
 			break;
-
-		case "array":
+		}
+		case "array": {
 			// In C++, arrays are never null - empty arrays (size() == 0) are equivalent to Java null
 			lines.push(`${indent}_json.writeArrayStart();`);
 			lines.push(`${indent}for (size_t i = 0; i < ${accessor}.size(); i++) {`);
@@ -113,7 +113,7 @@ function generatePropertyCode (property: Property, indent: string, enumMappings:
 			lines.push(`${indent}}`);
 			lines.push(`${indent}_json.writeArrayEnd();`);
 			break;
-
+		}
 		case "nestedArray":
 			// Nested arrays are always considered non-null in both Java and C++
 			lines.push(`${indent}_json.writeArrayStart();`);
@@ -148,7 +148,8 @@ function generateCppFromIR (ir: SerializerIR): string {
 	cppOutput.push('');
 	cppOutput.push('class SkeletonSerializer {');
 	cppOutput.push('private:');
-	cppOutput.push('    HashMap<void*, bool> _visitedObjects;');
+	cppOutput.push('    HashMap<void*, String> _visitedObjects;');
+	cppOutput.push('    int _nextId;');
 	cppOutput.push('    JsonWriter _json;');
 	cppOutput.push('');
 	cppOutput.push('public:');
@@ -161,6 +162,7 @@ function generateCppFromIR (ir: SerializerIR): string {
 		const cppParamType = transformType(method.paramType);
 		cppOutput.push(`    String ${method.name}(${cppParamType}* ${method.paramName}) {`);
 		cppOutput.push('        _visitedObjects.clear();');
+		cppOutput.push('        _nextId = 1;');
 		cppOutput.push('        _json = JsonWriter();');
 		cppOutput.push(`        ${method.writeMethodCall}(${method.paramName});`);
 		cppOutput.push('        return _json.getString();');
@@ -172,19 +174,46 @@ function generateCppFromIR (ir: SerializerIR): string {
 
 	// Generate write methods
 	for (const method of ir.writeMethods) {
-		const shortName = method.paramType.split('.').pop()!;
+		const shortName = method.paramType.split('.').pop();
 		const cppType = transformType(method.paramType);
 
 		// Custom writeSkin and writeSkinEntry implementations
 		if (method.name === 'writeSkin') {
 			cppOutput.push('    void writeSkin(Skin* obj) {');
 			cppOutput.push('        if (_visitedObjects.containsKey(obj)) {');
-			cppOutput.push('            _json.writeValue("<circular>");');
+			cppOutput.push('            _json.writeValue(_visitedObjects[obj]);');
 			cppOutput.push('            return;');
 			cppOutput.push('        }');
-			cppOutput.push('        _visitedObjects.put(obj, true);');
+
+			// Generate reference string for this object (only when first encountered)
+			// Only use name if there's a proper getName() method returning String
+			const nameGetter = method.properties.find(p =>
+				(p.kind === 'object' || p.kind === "primitive") &&
+				p.getter === 'getName()' &&
+				p.valueType === 'String'
+			);
+
+			if (nameGetter) {
+				// Use getName() if available and returns String
+				cppOutput.push('        String name = obj->getName();');
+				cppOutput.push('        String refString;');
+				cppOutput.push('        if (!name.isEmpty()) {');
+				cppOutput.push(`            refString.append("<${shortName}-").append(name).append(">");`);
+				cppOutput.push('        } else {');
+				cppOutput.push(`            refString.append("<${shortName}-").append(_nextId++).append(">");`);
+				cppOutput.push('        }');
+			} else {
+				// No suitable name getter - use numbered ID
+				cppOutput.push(`        String refString = String("<${shortName}-").append(_nextId++).append(">");`);
+			}
+			cppOutput.push('        _visitedObjects.put(obj, refString);');
+			cppOutput.push('');
 			cppOutput.push('');
 			cppOutput.push('        _json.writeObjectStart();');
+
+			cppOutput.push('        _json.writeName("refString");');
+			cppOutput.push('        _json.writeValue(refString);');
+
 			cppOutput.push('        _json.writeName("type");');
 			cppOutput.push('        _json.writeValue("Skin");');
 			cppOutput.push('');
@@ -230,6 +259,18 @@ function generateCppFromIR (ir: SerializerIR): string {
 			// Custom writeSkinEntry implementation
 			cppOutput.push('    void writeSkinEntry(Skin::AttachmentMap::Entry* obj) {');
 			cppOutput.push('        _json.writeObjectStart();');
+
+			// Generate refString using the name field if available
+			cppOutput.push('        String name = obj->_name;');
+			cppOutput.push('        String refString;');
+			cppOutput.push('        if (!name.isEmpty()) {');
+			cppOutput.push(`            refString.append("<${shortName}-").append(name).append(">");`);
+			cppOutput.push('        } else {');
+			cppOutput.push(`            refString.append("<${shortName}-").append(_nextId++).append(">");`);
+			cppOutput.push('        }');
+			cppOutput.push('        _json.writeName("refString");');
+			cppOutput.push('        _json.writeValue(refString);');
+
 			cppOutput.push('        _json.writeName("type");');
 			cppOutput.push('        _json.writeValue("SkinEntry");');
 			cppOutput.push('        _json.writeName("slotIndex");');
@@ -251,7 +292,7 @@ function generateCppFromIR (ir: SerializerIR): string {
 			if (method.subtypeChecks && method.subtypeChecks.length > 0) {
 				let first = true;
 				for (const subtype of method.subtypeChecks) {
-					const subtypeShortName = subtype.typeName.split('.').pop()!;
+					const subtypeShortName = subtype.typeName.split('.').pop();
 
 					if (first) {
 						cppOutput.push(`        if (obj->getRTTI().instanceOf(${subtypeShortName}::rtti)) {`);
@@ -271,14 +312,40 @@ function generateCppFromIR (ir: SerializerIR): string {
 			// Handle concrete types
 			// Add cycle detection
 			cppOutput.push('        if (_visitedObjects.containsKey(obj)) {');
-			cppOutput.push('            _json.writeValue("<circular>");');
+			cppOutput.push('            _json.writeValue(_visitedObjects[obj]);');
 			cppOutput.push('            return;');
 			cppOutput.push('        }');
-			cppOutput.push('        _visitedObjects.put(obj, true);');
+
+			// Generate reference string for this object (only when first encountered)
+			// Only use name if there's a proper getName() method returning String
+			const nameGetter = method.properties.find(p =>
+				(p.kind === 'object' || p.kind === "primitive") &&
+				p.getter === 'getName()' &&
+				p.valueType === 'String'
+			);
+
+			if (nameGetter) {
+				// Use getName() if available and returns String
+				cppOutput.push('        String name = obj->getName();');
+				cppOutput.push('        String refString;');
+				cppOutput.push('        if (!name.isEmpty()) {');
+				cppOutput.push(`            refString.append("<${shortName}-").append(name).append(">");`);
+				cppOutput.push('        } else {');
+				cppOutput.push(`            refString.append("<${shortName}-").append(_nextId++).append(">");`);
+				cppOutput.push('        }');
+			} else {
+				// No suitable name getter - use numbered ID
+				cppOutput.push(`        String refString = String("<${shortName}-").append(_nextId++).append(">");`);
+			}
+			cppOutput.push('        _visitedObjects.put(obj, refString);');
 			cppOutput.push('');
 
 			cppOutput.push('        _json.writeObjectStart();');
 
+			// Write reference string as first field for navigation
+			cppOutput.push('        _json.writeName("refString");');
+			cppOutput.push('        _json.writeValue(refString);');
+
 			// Write type field
 			cppOutput.push('        _json.writeName("type");');
 			cppOutput.push(`        _json.writeValue("${shortName}");`);
diff --git a/tests/src/generate-java-serializer.ts b/tests/src/generate-java-serializer.ts
index cb0a5fe28..125136904 100644
--- a/tests/src/generate-java-serializer.ts
+++ b/tests/src/generate-java-serializer.ts
@@ -40,7 +40,7 @@ function generatePropertyCode (property: Property, indent: string, method?: Writ
 			}
 			break;
 
-		case "array":
+		case "array": {
 			// Special handling for Skin attachments - sort by slot index
 			const isSkinAttachments = method?.paramType === 'Skin' && property.name === 'attachments' && property.elementType === 'SkinEntry';
 			const sortedAccessor = isSkinAttachments ? 'sortedAttachments' : accessor;
@@ -76,8 +76,8 @@ function generatePropertyCode (property: Property, indent: string, method?: Writ
 				lines.push(`${indent}json.writeArrayEnd();`);
 			}
 			break;
-
-		case "nestedArray":
+		}
+		case "nestedArray": {
 			if (property.isNullable) {
 				lines.push(`${indent}if (${accessor} == null) {`);
 				lines.push(`${indent}    json.writeNull();`);
@@ -108,6 +108,7 @@ function generatePropertyCode (property: Property, indent: string, method?: Writ
 				lines.push(`${indent}json.writeArrayEnd();`);
 			}
 			break;
+		}
 	}
 
 	return lines;
@@ -134,11 +135,12 @@ function generateJavaFromIR (ir: SerializerIR): string {
 	javaOutput.push('import com.badlogic.gdx.utils.FloatArray;');
 	javaOutput.push('');
 	javaOutput.push('import java.util.Locale;');
-	javaOutput.push('import java.util.Set;');
-	javaOutput.push('import java.util.HashSet;');
+	javaOutput.push('import java.util.Map;');
+	javaOutput.push('import java.util.HashMap;');
 	javaOutput.push('');
 	javaOutput.push('public class SkeletonSerializer {');
-	javaOutput.push('    private final Set<Object> visitedObjects = new HashSet<>();');
+	javaOutput.push('    private final Map<Object, String> visitedObjects = new HashMap<>();');
+	javaOutput.push('    private int nextId = 1;');
 	javaOutput.push('    private JsonWriter json;');
 	javaOutput.push('');
 
@@ -146,6 +148,7 @@ function generateJavaFromIR (ir: SerializerIR): string {
 	for (const method of ir.publicMethods) {
 		javaOutput.push(`    public String ${method.name}(${method.paramType} ${method.paramName}) {`);
 		javaOutput.push('        visitedObjects.clear();');
+		javaOutput.push('        nextId = 1;');
 		javaOutput.push('        json = new JsonWriter();');
 		javaOutput.push(`        ${method.writeMethodCall}(${method.paramName});`);
 		javaOutput.push('        json.close();');
@@ -156,7 +159,7 @@ function generateJavaFromIR (ir: SerializerIR): string {
 
 	// Generate write methods
 	for (const method of ir.writeMethods) {
-		const shortName = method.paramType.split('.').pop()!;
+		const shortName = method.paramType.split('.').pop();
 		const className = method.paramType.includes('.') ? method.paramType : shortName;
 
 		javaOutput.push(`    private void ${method.name}(${className} obj) {`);
@@ -166,7 +169,7 @@ function generateJavaFromIR (ir: SerializerIR): string {
 			if (method.subtypeChecks && method.subtypeChecks.length > 0) {
 				let first = true;
 				for (const subtype of method.subtypeChecks) {
-					const subtypeShortName = subtype.typeName.split('.').pop()!;
+					const subtypeShortName = subtype.typeName.split('.').pop();
 					const subtypeClassName = subtype.typeName.includes('.') ? subtype.typeName : subtypeShortName;
 
 					if (first) {
@@ -186,15 +189,35 @@ function generateJavaFromIR (ir: SerializerIR): string {
 		} else {
 			// Handle concrete types
 			// Add cycle detection
-			javaOutput.push('        if (visitedObjects.contains(obj)) {');
-			javaOutput.push('            json.writeValue("<circular>");');
+			javaOutput.push('        if (visitedObjects.containsKey(obj)) {');
+			javaOutput.push('            json.writeValue(visitedObjects.get(obj));');
 			javaOutput.push('            return;');
 			javaOutput.push('        }');
-			javaOutput.push('        visitedObjects.add(obj);');
+			
+			// Generate reference string for this object (only when first encountered)
+			// Only use name if there's a proper getName() method returning String
+			const nameGetter = method.properties.find(p =>
+				(p.kind === 'object' || p.kind === "primitive") &&
+				p.getter === 'getName()' &&
+				p.valueType === 'String'
+			);
+
+			if (nameGetter) {
+				// Use getName() if available and returns String
+				javaOutput.push(`        String refString = obj.getName() != null ? "<${shortName}-" + obj.getName() + ">" : "<${shortName}-" + (nextId++) + ">";`);
+			} else {
+				// No suitable name getter - use numbered ID
+				javaOutput.push(`        String refString = "<${shortName}-" + (nextId++) + ">";`);
+			}
+			javaOutput.push('        visitedObjects.put(obj, refString);');
 			javaOutput.push('');
 
 			javaOutput.push('        json.writeObjectStart();');
 
+			// Write reference string as first field for navigation
+			javaOutput.push('        json.writeName("refString");');
+			javaOutput.push('        json.writeValue(refString);');
+
 			// Write type field
 			javaOutput.push('        json.writeName("type");');
 			javaOutput.push(`        json.writeValue("${shortName}");`);
diff --git a/tests/src/headless-test-runner.ts b/tests/src/headless-test-runner.ts
index e4527c502..1bc763ea5 100755
--- a/tests/src/headless-test-runner.ts
+++ b/tests/src/headless-test-runner.ts
@@ -332,7 +332,7 @@ function executeCpp (args: TestArgs): string {
 		// Build using build.sh
 		log_action('Building C++ tests');
 		try {
-			execSync('./build.sh clean release', {
+			execSync('./build.sh clean debug', {
 				cwd: cppDir,
 				stdio: ['inherit', 'pipe', 'inherit']
 			});
@@ -593,7 +593,8 @@ function main (): void {
 	log_title('Spine Runtime Test');
 
 	// Clean output directory first
-	cleanOutputDirectory();
+	// TODO annoying during development of generators as it also smokes generator outputs
+	// cleanOutputDirectory();
 
 	if (args.files) {
 		// Auto-discovery mode: run tests for both JSON and binary files
diff --git a/todos/work/2025-01-11-03-02-54-test-suite/task.md b/todos/done/2025-01-11-03-02-54-test-suite.md
similarity index 100%
rename from todos/work/2025-01-11-03-02-54-test-suite/task.md
rename to todos/done/2025-01-11-03-02-54-test-suite.md
diff --git a/todos/done/2025-01-21-18-49-54-logging-indentation.md b/todos/done/2025-01-21-18-49-54-logging-indentation.md
new file mode 100644
index 000000000..3d969f64c
--- /dev/null
+++ b/todos/done/2025-01-21-18-49-54-logging-indentation.md
@@ -0,0 +1,22 @@
+# Improve bash script logging indentation for nested calls
+**Status:** Done
+**Agent PID:** 30228
+
+## Original Todo
+- clean up logging in spine-c/codegen, use chalk to do colored warnings/errors and make logging look very nice and informative (no emojis)
+
+## Description
+Implement automatic indentation for bash script logging when scripts call other scripts. Currently, when a script calls another script, both use the same logging functions from `formatters/logging/logging.sh`, making it difficult to distinguish the call hierarchy. The solution will detect script nesting level by analyzing the process tree and automatically indent log output from child scripts.
+
+## Implementation Plan
+- [x] Create process tree analysis utility to detect script nesting level
+- [x] Add nesting level detection that runs once when logging.sh is sourced
+- [x] Store indentation level in a local variable (SPINE_LOG_INDENT_SPACES) - **not exported**
+- [x] Modify log_action(), log_warn(), and log_detail() to use the pre-calculated local indentation
+- [x] Test with nested script calls (format.sh calling format-cpp.sh, etc.)
+- [x] Ensure backward compatibility and graceful fallback if detection fails
+- [x] Update documentation to explain the new indentation behavior
+- [x] Add script filename to log_title output for better clarity
+
+## Notes
+26 bash scripts in the codebase use logging.sh functionality, including build, test, format, setup, and publish scripts. All would benefit from proper indentation when calling each other.
\ No newline at end of file
diff --git a/todos/done/2025-01-21-19-06-33-circular-reference-display-analysis.md b/todos/done/2025-01-21-19-06-33-circular-reference-display-analysis.md
new file mode 100644
index 000000000..1206bc7b0
--- /dev/null
+++ b/todos/done/2025-01-21-19-06-33-circular-reference-display-analysis.md
@@ -0,0 +1,74 @@
+# Circular Reference Display Analysis
+
+## Current Implementation
+
+The circular reference detection is implemented in:
+
+### 1. **Java SkeletonSerializer** 
+**File:** `spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/utils/SkeletonSerializer.java`
+- Uses pattern: `if (visitedObjects.contains(obj)) { json.writeValue("<circular>"); return; }`
+- Found on 100+ lines throughout write methods
+
+### 2. **C++ SkeletonSerializer**
+**File:** `spine-cpp/tests/SkeletonSerializer.h`
+- Uses pattern: `if (_visitedObjects.containsKey(obj)) { _json.writeValue("<circular>"); return; }`
+- Similar implementation to Java version
+
+### 3. **Generator Scripts**
+- `tests/src/generate-java-serializer.ts` (lines 189-192)
+- `tests/src/generate-cpp-serializer.ts` (lines 182-183, 274-275)
+- Both inject the circular reference detection pattern
+
+### 4. **Test Runner**
+- `tests/src/headless-test-runner.ts` (line 409)
+- Handles "<circular>" values during JSON comparison
+
+## Object Identification Patterns
+
+### Name-based Identification
+Most Spine objects use `name` as primary identifier:
+```java
+// Event.java - toString returns the event's name
+public String toString() { return data.name; }
+
+// Attachment.java - toString returns attachment name  
+public String toString() { return name; }
+
+// Skeleton.java - toString returns skeleton data name or falls back
+public String toString() {
+    return data.name != null ? data.name : super.toString();
+}
+```
+
+### ID-based Identification
+TypeScript VertexAttachment uses auto-incrementing IDs:
+```typescript
+export abstract class VertexAttachment extends Attachment {
+    private static nextID = 0;
+    /** The unique ID for this attachment. */
+    id = VertexAttachment.nextID++;
+}
+```
+
+### Type-based Identification
+Serializers include explicit type information:
+```java
+json.writeName("type");
+json.writeValue("Animation");
+```
+
+## Current Limitations
+
+1. **No type information** - Can't quickly understand what type of object caused the circular reference
+2. **No unique identification** - Can't distinguish between multiple circular references of the same type  
+3. **No navigation aid** - Can't easily locate the original object definition in large object graphs
+
+## Enhancement Opportunities
+
+The existing infrastructure supports enhancement:
+- Consistent naming patterns across objects
+- Unique ID patterns could be expanded
+- Type information already captured in serializers
+- Object reference tracking infrastructure is mature
+
+Enhanced format could be: `<circular: Animation#"walk">` or `<circular: Bone#"head">` instead of just `<circular>`.
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diff --git a/todos/done/2025-01-21-19-06-33-circular-reference-display.md b/todos/done/2025-01-21-19-06-33-circular-reference-display.md
new file mode 100644
index 000000000..4c33c5afd
--- /dev/null
+++ b/todos/done/2025-01-21-19-06-33-circular-reference-display.md
@@ -0,0 +1,35 @@
+# Circular Reference Display Enhancement
+**Status:** Done
+**Agent PID:** 67832
+
+## Original Todo
+<circular> should include the type and a unique id for the object, so i can quckly understand what's been omitted navigate to it
+
+## Description
+Replace "<circular>" with deterministic object identifiers in Spine serializers. The implementation uses a hybrid approach: objects with name properties use "<ObjectType-name>" format (e.g. "<EventData-walk>"), while objects without names use numbered IDs "<ObjectType-1>", "<ObjectType-2>", etc. This ensures identical output across Java/C++ by using deterministic reference strings that are generated only when objects are first encountered.
+
+## Implementation Plan
+- [x] Update Java generator script - Modified `tests/src/generate-java-serializer.ts` to use Map<Object, String> visitedObjects with `nextId` counter, generating name-based or numbered reference strings
+- [x] Update C++ generator script - Modified `tests/src/generate-cpp-serializer.ts` to use HashMap<void*, String> with `_nextId` counter, matching Java logic with proper Spine String API usage
+- [x] Regenerate serializers - Generated updated Java and C++ SkeletonSerializer classes with new circular reference handling
+- [x] Fix deterministic IDs - Implemented hybrid system: `<Type-name>` for named objects, `<Type-N>` for unnamed objects, ensuring identical output across languages
+- [x] Update test runner - Test runner handles new circular reference format correctly
+- [x] Automated test: Serialization tests pass with no regressions
+- [x] User test: Circular references now show meaningful format like `<EventData-walk>` or `<Animation-1>` instead of `<circular>`
+- [x] Add reference string field: Include refString as first field in each object's JSON to enable quick navigation from circular references to full objects
+
+## Notes
+### Implementation Details:
+- **Circular Reference Logic**: Changed from simple boolean tracking to String-based reference storage
+- **Reference String Generation**: Only occurs when object is first encountered (after cycle detection check)
+- **Name Detection**: Uses `p.getter === 'getName()' && p.valueType === 'String'` to identify objects with meaningful names
+- **Deterministic Numbering**: Both Java and C++ use identical counter logic, ensuring same numbered IDs for unnamed objects
+- **Types with Names**: BoneData, EventData, IkConstraintData, PathConstraintData, PhysicsConstraintData, Animation, and attachment types
+- **Output Format**: 
+  - Named: `<EventData-walk>`, `<BoneData-head>`, `<Animation-run>`
+  - Unnamed: `<TrackEntry-1>`, `<Bone-2>`, `<SliderTimeline-3>`
+- **Navigation Enhancement**: Each serialized object includes `"refString"` as its first field, making it easy to jump from circular reference to full object definition
+
+### Commands:
+- `tests/generate-serializers.sh` -> generates the serializers
+- `tests/test.sh cpp -s spineboy -f` -> compiles and runs the tests, and outputs whether the generated json files are identical
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diff --git a/todos/todos.md b/todos/todos.md
index d86d77e6e..938b572e4 100644
--- a/todos/todos.md
+++ b/todos/todos.md
@@ -1,4 +1,3 @@
-- clean up logging in spine-c/codegen, use chalk to do colored warnings/errors and make logging look very nice and informative (no emojis)
 - spine-c/codegen type extractor should also report typedefs like typedef long long PropertyId; so primitive type to some name, and we need to handle that in the codegen
 - Generate language bindings in spine-c/codegen
     - Use CClassOrStruct, CEnum that get generated from spine-cpp-types.json and generate