Lynda Thomas Mark Ratcliffe Benjy J. Thomasson Can Object (Instance) Diagrams Help First Year Students Understand Program Behaviour? 368-371 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2980&spage=368 2004 conf/diagrams/2004 Diagrams db/conf/diagrams/diagrams2004.html#ThomasRT04