%% You should probably cite draft-mahy-mls-content-adv instead of this I-D.
@techreport{mahy-mls-content-neg-00,
    number =    {draft-mahy-mls-content-neg-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-mahy-mls-content-neg/00/},
    author =    {Rohan Mahy},
    title =     {{Content Negotiation for Message Layer Security (MLS)}},
    pagetotal = 7,
    year =      2022,
    month =     mar,
    day =       31,
    abstract =  {This document describes a default mechanism for the negotiation of content inside an MLS group. It defines two new extensions to the MLS (Messaging Layer Security) Protocol to allow for negotiation of media types exchanged among members of an MLS group, and a minimal framing format.},
}