Eric A. Meyer; Bert Bos. <a href="http://www.w3.org/TR/2001/WD-css3-roadmap-20010523"><cite>CSS3 introduction.</cite></a> 23 May 2001. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2001/WD-css3-roadmap-20010523">http://www.w3.org/TR/2001/WD-css3-roadmap-20010523</a>