Jon Phipps; Daniel Rubin; Antoine Isaac. <a href="http://www.w3.org/TR/2007/WD-skos-ucr-20070516"><cite>SKOS Use Cases and Requirements.</cite></a> 16 May 2007. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2007/WD-skos-ucr-20070516">http://www.w3.org/TR/2007/WD-skos-ucr-20070516</a>