%% You should probably cite rfc5518 instead of this I-D.
@techreport{hoffman-dac-vbr-07,
    number =    {draft-hoffman-dac-vbr-07},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-hoffman-dac-vbr/07/},
    author =    {Arvel Hathcock and John R. Levine and Paul E. Hoffman},
    title =     {{Vouch By Reference}},
    pagetotal = 12,
    year =      2009,
    month =     feb,
    day =       25,
    abstract =  {This document describes the Vouch By Reference (VBR) protocol. VBR is a protocol for adding third-party certification to email. It permits independent third parties to certify the owner of a domain name that is associated with received mail. {[}STANDARDS-TRACK{]}},
}