The W3C Semantic Web Best Practices and Deployment Working Group has published the first working draft of XML Schema Datatypes in RDF and OWL. According to the abstract, "The RDF and OWL Recommendations use the simple types from XML Schema. This document discusses three questions left unanswered by these Recommendations: What URIref should be used to refer to a user defined datatype? Which values of which XML Schema simple types are the same? How to use the problematic xsd:duration in RDF and OWL? In addition, we further describe how to integrate OWL DL with user defined datatypes."