W3C:

2008-03-17: The Semantic Web Deployment Working Group and the XHTML2 Working Group have jointly published an updated Working Draft of the RDFa Primer 1.0. The primer is an introduction to RDFa, a method for embedding structured data in XHTML. Changes in this draft align it with the the interpretation of the @src attribute as specified in the 21 February 2008 RDFa Syntax Last Call Working Draft. Visit the XHTML2 and Semantic Web home pages. (Permalink)