Jordi Conesa Xavier de Palol Antoni Olivé Building Conceptual Schemas by Refining General Ontologies. 693-702 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2736&spage=693 2003 conf/dexa/2003 DEXA db/conf/dexa/dexa2003.html#ConesaPO03