%% You should probably cite draft-ietf-jcardcal-jcard instead of this I-D.
@techreport{bhat-vcarddav-json-00,
    number =    {draft-bhat-vcarddav-json-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-bhat-vcarddav-json/00/},
    author =    {Raghurama Bhat and Peter Saint-Andre},
    title =     {{A JavaScript Object Notation (JSON) Representation for vCard}},
    pagetotal = 10,
    year =      2012,
    month =     jun,
    day =       6,
    abstract =  {This document defines a representation of vCard data in JavaScript Object Notation (JSON).},
}