%% You should probably cite rfc3885 instead of this I-D.
@techreport{ietf-msgtrk-smtpext-05,
    number =    {draft-ietf-msgtrk-smtpext-05},
    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-msgtrk-smtpext/05/},
    author =    {Tony Hansen and Eric P. Allman},
    title =     {{SMTP Service Extension for Message Tracking}},
    pagetotal = 9,
    year =      2003,
    month =     apr,
    day =       1,
    abstract =  {This memo defines an extension to the SMTP service whereby a client may mark a message for future tracking. {[}STANDARDS-TRACK{]}},
}