%% You should probably cite draft-ietf-mailmaint-expires instead of this I-D.
@techreport{billon-expires-10,
    number =    {draft-billon-expires-10},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-billon-expires/10/},
    author =    {Benjamin BILLON and John R. Levine},
    title =     {{Updated Use of the Expires Message Header Field}},
    pagetotal = 6,
    year =      2024,
    month =     jul,
    day =       5,
    abstract =  {This document allows broader use of the Expires message header field for mail messages. Message creators can then indicate when a message expires, while recipients would use this information to handle an expired message differently.},
}