Dan Corbett Wendy Mayer Concept Type Hierarchy as Ontology: An Example Historical Knowledge Base. 259-271 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3339&spage=259 2004 conf/ausai/2004 Australian Conference on Artificial Intelligence db/conf/ausai/ausai2004.html#CorbettM04