Valentina Popescu; Virginia Smith; Bhalchandra Pandit. <a href="http://www.w3.org/TR/2009/PR-sml-20090212"><cite>Service Modeling Language, Version 1.1.</cite></a> 12 February 2009. W3C Proposed Recommendation. (Work in progress.) URL: <a href="http://www.w3.org/TR/2009/PR-sml-20090212">http://www.w3.org/TR/2009/PR-sml-20090212</a>