Bert Bos. <a href="http://www.w3.org/TR/2007/WD-css3-box-20070809"><cite>CSS basic box model.</cite></a> 9 August 2007. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2007/WD-css3-box-20070809">http://www.w3.org/TR/2007/WD-css3-box-20070809</a>