%% You should probably cite rfc4239 instead of this I-D.
@techreport{ietf-vpim-ivm-06,
    number =    {draft-ietf-vpim-ivm-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-ietf-vpim-ivm/06/},
    author =    {Stuart McRae and Glenn Parsons},
    title =     {{Internet Voice Messaging (IVM)}},
    pagetotal = 11,
    year =      2004,
    month =     jun,
    day =       17,
    abstract =  {This document describes the carriage of voicemail messages over Internet mail as part of a unified messaging infrastructure. The Internet Voice Messaging (IVM) concept described in this document is not a successor format to VPIM v2 (Voice Profile for Internet Mail Version 2), but rather an alternative specification for a different application. {[}STANDARDS-TRACK{]}},
}