Ahmed Arara Djamal Benslimane Towards Formal Ontologies Requirements with Multiple Perspectives. 150-160 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3055&spage=150 2004 conf/fqas/2004 FQAS db/conf/fqas/fqas2004.html#AraraB04