%% You should probably cite rfc8550 instead of this I-D.
@techreport{ietf-lamps-rfc5750-bis-06,
    number =    {draft-ietf-lamps-rfc5750-bis-06},
    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-lamps-rfc5750-bis/06/},
    author =    {Jim Schaad and Blake C. Ramsdell and Sean Turner},
    title =     {{Secure/Multipurpose Internet Mail Extensions (S/ MIME) Version 4.0 Certificate Handling}},
    pagetotal = 26,
    year =      2018,
    month =     may,
    day =       3,
    abstract =  {This document specifies conventions for X.509 certificate usage by Secure/Multipurpose Internet Mail Extensions (S/MIME) v4.0 agents. S/MIME provides a method to send and receive secure MIME messages, and certificates are an integral part of S/MIME agent processing. S/MIME agents validate certificates as described in RFC 5280, the Internet X.509 Public Key Infrastructure Certificate and CRL Profile. S/MIME agents must meet the certificate processing requirements in this document as well as those in RFC 5280. This document obsoletes RFC 5750.},
}