Markus Lauff; Amy Yu. <a href="http://www.w3.org/TR/2003/WD-cpc-req-20030510"><cite>Core Presentation Characteristics:&#160;Requirements and Use Cases.</cite></a> 10 May 2003. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2003/WD-cpc-req-20030510">http://www.w3.org/TR/2003/WD-cpc-req-20030510</a>