IVOA Recommendation: VOTable Format Definition Version 1.3
  This document describes the structures making up the VOTable standard. The main part of this document describes the adopted part of the VOTable standard; it is followed by appendices presenting extensions which have been proposed and/or discussed, but which are not part of the standard. 
Fran\c{c}ois Ochsenbein, Roy Williams, Clive Davenhall, Daniel Durand,   Pierre Fernique, David Giaretta, Robert Hanisch, To...
astro-ph.IM