%% You should probably cite draft-ietf-vcarddav-vcardxml instead of this I-D.
@techreport{perreault-vcarddav-vcardxml-02,
    number =    {draft-perreault-vcarddav-vcardxml-02},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-perreault-vcarddav-vcardxml/02/},
    author =    {Simon Perreault},
    title =     {{vCard XML Schema}},
    pagetotal = 11,
    year =      2009,
    month =     jul,
    day =       13,
    abstract =  {This document defines the XML schema of the vCard data format.},
}