Cliff Joslyn Poset Ontologies and Concept Lattices as Semantic Hierarchies. 287-302 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3127&spage=287 2004 conf/iccs/2004 ICCS db/conf/iccs/iccs2004.html#Joslyn04