 This data structure is a list of lists.  The inner lists are names that should that
	 * should be created in the same linkage.  The outer list collects the heads of the
	 * inner lists.
 This data structure is a list of lists.  The inner lists are names that should that
	 * should be created in the same linkage.  The outer list collects the heads of the
	 * inner lists. | PDOMExternalReferencesList.java