Walter W. Chang. <a href="http://www.w3.org/TR/1998/NOTE-rdf-uml-19980804"><cite>A Discussion of the Relationship Between RDF-Schema and UML.</cite></a> 4 August 1998. W3C Note. URL: <a href="http://www.w3.org/TR/1998/NOTE-rdf-uml-19980804">http://www.w3.org/TR/1998/NOTE-rdf-uml-19980804</a>