Dean Jackson; David Hyatt; Chris Marrin. <a href="http://www.w3.org/TR/2009/WD-css3-transitions-20090320"><cite>CSS Transitions Module Level 3.</cite></a> 20 March 2009. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2009/WD-css3-transitions-20090320">http://www.w3.org/TR/2009/WD-css3-transitions-20090320</a>