Natasha Noy; Alan Rector. <a href="http://www.w3.org/TR/2006/NOTE-swbp-n-aryRelations-20060412"><cite>Defining N-ary Relations on the Semantic Web.</cite></a> 12 April 2006. W3C Note. URL: <a href="http://www.w3.org/TR/2006/NOTE-swbp-n-aryRelations-20060412">http://www.w3.org/TR/2006/NOTE-swbp-n-aryRelations-20060412</a>