Jeff Z. Pan Ian Horrocks RDFS(FA) and RDF MT: Two Semantics for RDFS. 30-46 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2870&spage=30 2003 conf/semweb/2003 International Semantic Web Conference db/conf/semweb/iswc2003.html#PanH03