Frederick Hirsch. <a href="http://www.w3.org/TR/2010/WD-xmldsig-properties-20100204/"><cite>XML Signature Properties.</cite></a> 4 February 2010. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2010/WD-xmldsig-properties-20100204/">http://www.w3.org/TR/2010/WD-xmldsig-properties-20100204/</a>