Guizhen Yang Michael Kifer Inheritance and Rules in Object-Oriented Semantic Web Languages. 95-110 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2876&spage=95 2003 conf/semweb/2003ruleml RuleML db/conf/semweb/ruleml2003.html#YangK03