diff --git a/src/org/ntlab/deltaViewer/CollaborationLayout.java b/src/org/ntlab/deltaViewer/CollaborationLayout.java
index bf3aad3..76674f9 100644
--- a/src/org/ntlab/deltaViewer/CollaborationLayout.java
+++ b/src/org/ntlab/deltaViewer/CollaborationLayout.java
@@ -83,7 +83,7 @@
 		}
 		
 		// Extract the reference access history.
-		List<Reference> references = objectCallGraph.getReferences();
+		List<Reference> references = new ArrayList<>(objectCallGraph.getReferences());
 		Map<Reference, List<Integer>> referenceHistory = new HashMap<>();
 		int order = 0;
 		for (Alias a: aliasCollector.getAliasList()) {
@@ -106,13 +106,28 @@
 			} else if (a.getAliasType() == AliasType.RETURN_VALUE) {
 				MethodExecution methodExec = a.getMethodExecution();
 				if (methodExec.getSignature().contains("List.get(") ||
-						methodExec.getSignature().contains("Map.get(")) {
+						methodExec.getSignature().contains("Map.get(") ||
+						methodExec.getSignature().contains(".next()") ||
+						methodExec.getSignature().contains(".iterator()") ||
+						methodExec.getSignature().contains(".listIterator()")) {
 					String srcObjId = methodExec.getThisObjId();
 					String dstObjId = methodExec.getReturnValue().getId();
 					String srcClassName = methodExec.getThisClassName();
 					String dstClassName = methodExec.getReturnValue().getActualType();
 					idx = references.indexOf(new Reference(srcObjId, dstObjId, srcClassName, dstClassName));
-				}				
+				} else if (methodExec.isStatic() && methodExec.getCallerMethodExecution().isStatic()) {
+					// For calls from a static method to another static method.
+					String dstClassName = methodExec.getThisClassName();
+					String srcClassName = methodExec.getCallerMethodExecution().getThisClassName();
+					String dstObjId = methodExec.getThisObjId() + ":" + dstClassName;
+					String srcObjId = methodExec.getCallerMethodExecution().getThisObjId() + ":" + srcClassName;
+					Reference r = new Reference(srcObjId, dstObjId, srcClassName, dstClassName);
+					idx = references.indexOf(r);
+					if (idx < 0) {
+						references.add(r);
+						idx = references.indexOf(r);
+					}					
+				}
 			} else if (a.getAliasType() == AliasType.CONSTRACTOR_INVOCATION) {
 				MethodInvocation c = (MethodInvocation) a.getOccurrencePoint().getStatement();
 				String srcObjId = a.getMethodExecution().getThisObjId();
diff --git a/src/org/ntlab/deltaViewer/CollaborationViewer.java b/src/org/ntlab/deltaViewer/CollaborationViewer.java
index 671fce7..b2b0cf8 100644
--- a/src/org/ntlab/deltaViewer/CollaborationViewer.java
+++ b/src/org/ntlab/deltaViewer/CollaborationViewer.java
@@ -480,6 +480,10 @@
 						srcClassName = nextMethodExec.getThisClassName();
 						fieldName = "";
 						System.out.println(TAG + ": Create Map of Edge.(ClassName=" + srcClassName + ")");
+					} else if (nextMethodExec.getSignature().contains(".next()") || nextMethodExec.getSignature().contains(".iterator()") || nextMethodExec.getSignature().contains(".listIterator()")) {
+						srcClassName = nextMethodExec.getThisClassName();
+						fieldName = "";
+						System.out.println(TAG + ": Create List Iterator of Edge.(ClassName=" + srcClassName + ")");
 					}
 				} else {
 					if (nextAlias.getAliasType() == AliasType.FIELD) { // When final local.
diff --git a/src/org/ntlab/deltaViewer/DeltaViewer.java b/src/org/ntlab/deltaViewer/DeltaViewer.java
index 2294bb9..7a96622 100644
--- a/src/org/ntlab/deltaViewer/DeltaViewer.java
+++ b/src/org/ntlab/deltaViewer/DeltaViewer.java
@@ -549,10 +549,17 @@
 					MethodExecution nextMethodExec = nextAlias.getMethodExecution();
 					//Array��List�̂Ƃ��������x����t����i�m���ɕ������Ă�����̂Ƃ�)getSignature->contains("List.get(") || "Map.get(") <�z���C�g���X�g>
 					if (nextMethodExec.getSignature().contains("List.get(") ||
-							nextMethodExec.getSignature().contains("Map.get(")) {
+							nextMethodExec.getSignature().contains("Map.get(") || 
+							nextMethodExec.getSignature().contains(".next()") ||
+							nextMethodExec.getSignature().contains(".iterator()") ||
+							nextMethodExec.getSignature().contains(".listIterator()")) {
 						srcClassName = nextMethodExec.getThisClassName();
-						fieldName = nextMethodExec.getArguments().get(0).getId();
-						System.out.println("rTHIS " + srcClassName + ", " + nextMethodExec.getArguments().get(0).getId());
+						if (nextMethodExec.getArguments().size() > 0) {
+							fieldName = nextMethodExec.getArguments().get(0).getId();
+						} else {
+							fieldName = "";
+						}
+						System.out.println("rTHIS " + srcClassName + ", " + fieldName);
 					}
 				} else {
 					Statement statement = nextAlias.getOccurrencePoint().getStatement();
diff --git a/src/org/ntlab/deltaViewer/ForwardAliasCollector.java b/src/org/ntlab/deltaViewer/ForwardAliasCollector.java
index 93ca42f..f0d48e1 100644
--- a/src/org/ntlab/deltaViewer/ForwardAliasCollector.java
+++ b/src/org/ntlab/deltaViewer/ForwardAliasCollector.java
@@ -138,7 +138,10 @@
 						addAlias(methodInvAlias);
 					}
 					if (methodSignature.contains("List.get(") ||
-							methodSignature.contains("Map.get(")) {
+							methodSignature.contains("Map.get(") ||
+							methodSignature.contains(".next()") ||
+							methodSignature.contains(".iterator()") ||
+							methodSignature.contains(".listIterator()")) {
 						String returnClass = mi.getCalledMethodExecution().getReturnValue().getActualType();
 						Reference ref = new Reference(mi.getCalledMethodExecution().getThisObjId(), returnValue, mi.getCalledMethodExecution().getThisClassName(), returnClass);
 						ref.setCollection(true);
diff --git a/src/org/ntlab/deltaViewer/ForwardLayout.java b/src/org/ntlab/deltaViewer/ForwardLayout.java
index 893535f..021fb0c 100644
--- a/src/org/ntlab/deltaViewer/ForwardLayout.java
+++ b/src/org/ntlab/deltaViewer/ForwardLayout.java
@@ -51,7 +51,10 @@
 			} else if (a.getAliasType() == AliasType.RETURN_VALUE) {
 				MethodExecution methodExec = a.getMethodExecution();
 				if (methodExec.getSignature().contains("List.get(") ||
-						methodExec.getSignature().contains("Map.get(")) {
+						methodExec.getSignature().contains("Map.get(") || 
+						methodExec.getSignature().contains(".next()") ||
+						methodExec.getSignature().contains(".iterator()") ||
+						methodExec.getSignature().contains(".listIterator()")) {
 					String srcObjId = methodExec.getThisObjId();
 					String dstObjId = methodExec.getReturnValue().getId();
 					String srcClassName = methodExec.getThisClassName();