Dan Corbett Comparing and Merging Ontologies: A Concept Type Hierarchy Approach. 75-82 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2871&spage=75 2003 conf/ismis/2003 ISMIS db/conf/ismis/ismis2003.html#Corbett03