Ian Horrocks Peter F. Patel-Schneider Reducing OWL Entailment to Description Logic Satisfiability. 17-29 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2870&spage=17 2003 conf/semweb/2003 International Semantic Web Conference db/conf/semweb/iswc2003.html#HorrocksP03