Elika J. Etemad; Bert Bos. <a href="http://www.w3.org/TR/2008/WD-css3-background-20080910"><cite>CSS Backgrounds and Borders Module Level 3.</cite></a> 10 September 2008. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2008/WD-css3-background-20080910">http://www.w3.org/TR/2008/WD-css3-background-20080910</a>