The Numismatic Description Schema is a codified XML schema based on numismatic database fields proposed by Sebastian Heath and Andrew Meadows. These fields, called the Numismatic Description Standard, are detailed at http://www.greekcoinage.org/nuds.html, and were originally published on Nomisma.org. The NUDS XML schema is based on this field list and Ethan Gruber's preliminary work mapping coins to Encoded Archival Description, which was detailed in a 2009 Computer Applications in Archaeology paper, "Encoded Archival Description for Numismatic Collections". It is also influenced by the structure of TEI and EAC-CPF, common standards in the Digital Humanities, library and archival domains. Ideally, a NUDS record should implement XLink attributes to integrate URIs to external controlled Linked Open Data controlled vocabulary systems, such as concepts defined on Nomisma.org itself.
Full documentation is available at http://nomisma.org/nuds.