%% You should probably cite rfc5451 instead of this I-D.
@techreport{kucherawy-sender-auth-header-20,
    number =    {draft-kucherawy-sender-auth-header-20},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-kucherawy-sender-auth-header/20/},
    author =    {Murray Kucherawy},
    title =     {{Message Header Field for Indicating Message Authentication Status}},
    pagetotal = 43,
    year =      2009,
    month =     jan,
    day =       21,
    abstract =  {This memo defines a new header field for use with electronic mail messages to indicate the results of message authentication efforts. Any receiver-side software, such as mail filters or Mail User Agents (MUAs), may use this message header field to relay that information in a convenient way to users or to make sorting and filtering decisions. {[}STANDARDS-TRACK{]}},
}