Hi Morris, this document contains examples for the idea of using XQuery to express requirement on an XML-based resource description (in this case this is GLUE 2.0) http://ogf.org/documents/GFD.137.pdf The advantage of this approach is that JSDL is not bound to a set of terms and does not need to be changed according to the evolution of the information model. Cheers, Sergio -- Sergio Andreozzi - Policy Development Manager EGI.eu - Amsterdam - The Netherlands - http://egi.eu