%% You should probably cite draft-ietf-marf-base instead of this I-D.
@techreport{shafranovich-feedback-report-08,
    number =    {draft-shafranovich-feedback-report-08},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-shafranovich-feedback-report/08/},
        author =    {Yakov Shafranovich and John R. Levine and Murray Kucherawy},
    title =     {{An Extensible Format for Email Feedback Reports}},
    pagetotal = 37,
    year =      2009,
    month =     oct,
    day =       20,
    abstract =  {This document defines an extensible format and MIME type that may be used by network operators to report feedback about received email to other parties. This format is intended as a machine-readable replacement for various existing report formats currently used in Internet email.},
}