Michael Smith; Ian Horrocks; Markus Kr&#246;tzsch; Birte Glimm. <a href="http://www.w3.org/TR/2009/REC-owl2-conformance-20091027/"><cite>OWL 2 Web Ontology Language:Conformance.</cite></a> 27 October 2009. W3C Recommendation.  URL: <a href="http://www.w3.org/TR/2009/REC-owl2-conformance-20091027/">http://www.w3.org/TR/2009/REC-owl2-conformance-20091027/</a>