%% You should probably cite draft-ietf-sip-domain-certs instead of this I-D.
@techreport{gurbani-sip-domain-certs-06,
    number =    {draft-gurbani-sip-domain-certs-06},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-gurbani-sip-domain-certs/06/},
    author =    {Vijay K. Gurbani},
    title =     {{Domain Certificates in the Session Initiation Protocol (SIP)}},
    pagetotal = 17,
    year =      2007,
    month =     jul,
    day =       10,
    abstract =  {This document provides a profile of PKIX-compliant certificates for the purpose of domain authentication in the Session Initiation Protocol (SIP).},
}