%% You should probably cite rfc2789 instead of this I-D.
@techreport{ietf-madman-email-mib-05,
    number =    {draft-ietf-madman-email-mib-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-madman-email-mib/05/},
    author =    {MessagingDirect Inc and Ned Freed},
    title =     {{Mail Monitoring MIB}},
    pagetotal = 33,
    year =      1999,
    month =     dec,
    day =       23,
    abstract =  {This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. Specifically, this memo extends the basic Network Services Monitoring MIB defined in RFC 2788 {[}STANDARDS-TRACK{]}},
}