%% You should probably cite rfc1869 instead of this I-D.
@techreport{ietf-smtpext-extensions-04,
    number =    {draft-ietf-smtpext-extensions-04},
    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-smtpext-extensions/04/},
    author =    {Dave Crocker and Dr. John C. Klensin and Einar A. Stefferud and Dr. Marshall T. Rose and Ned Freed},
    title =     {{SMTP Service Extensions}},
    pagetotal = 11,
    year =      1995,
    month =     may,
    day =       8,
    abstract =  {This memo defines a framework for extending the SMTP service by defining a means whereby a server SMTP can inform a client SMTP as to the service extensions it supports. {[}STANDARDS-TRACK{]}},
}