Roman and Aaron, If I understood correctly: Roman liked id/idRef "to make distinction between definitions and references to those definitions." Aaron does not have a strong opinion about id/idRef but likes "the idea based around inheritance." I previously proposed (artf6555) id/idRef to distinguish between authority ("id meaning 'this is my resource, I can tell you all about it' and idRef meaning 'I'm just pointing to someone else's resource') So far the good news. The bad news is a practical problem I have in translating from RDF to XML. RDF does not contain id or idRef attributes. So when I take some RDF-NML description and want to translate this to XML-NML, when exactly do I use "id" and when do I use "idRef"? This is not apparent to me, but the standard need to describe this rule in detail. So either we: 1. Add some additional info to RDF which determines when id and when idRef should be used in XML. 2. pick id or idRef in XML purely based on the syntax, but not on any semantics (e.g. an XML element without children uses idRef, an XML element with children uses id) 3. Remove idRef and just use id everywhere I prefer #3 over #2 for simplicity, but can imagine that #1 is really what we want. Roman and/or Aaron, could either of you come up with a clear proposal for #1? Freek