Lars Schoolmann Rudolf Wille Concept Graphs with Subdivision: A Semantic Approach. 271-281 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2746&spage=271 2003 conf/iccs/2003 ICCS db/conf/iccs/iccs2003.html#SchoolmannW03