Hi, the DOI system supports some metadata lookup via HTTP content-negotiation. I found this blog post talking about CrossRef's support: http://www.crossref.org/CrossTech/2011/04/content_negotiation_for_crossr.html But I know DataCite supports it to some extent too. Does anyone know if there's overall registrar-agnostic documentation from DOI for this service? Or, if there's kept-updated documentation from CrossRef and/or DataCite on it? From that blog post, it says rdf+xml, turtle, and atom+xml should all be supported as response formats. But atom+xml seems to not be supported -- if I try the very example from that blog post, I just get a 406 "No Acceptable Resource Available". I am not sure if this is a bug, or if CrossRef at a later point than that blog post decided not to support atom+xml. Anyone know how I'd find out, or get more information? Jonathan