%% You should probably cite rfc9071 instead of this I-D.
@techreport{ietf-avtcore-multi-party-rtt-mix-14,
    number =    {draft-ietf-avtcore-multi-party-rtt-mix-14},
    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-avtcore-multi-party-rtt-mix/14/},
    author =    {Gunnar Hellstrom},
    title =     {{RTP-mixer formatting of multi-party Real-time text}},
    pagetotal = 43,
    year =      2021,
    month =     apr,
    day =       11,
    abstract =  {Enhancements for RFC 4103 real-time text mixing are provided in this document, suitable for a centralized conference model that enables source identification and rapidly interleaved transmission of text from different sources. The intended use is for real-time text mixers and participant endpoints capable of providing an efficient presentation or other treatment of a multi-party real-time text session. The specified mechanism builds on the standard use of the CSRC list in the RTP packet for source identification. The method makes use of the same "text/t140" and "text/red" formats as for two- party sessions. Solutions using multiple RTP streams in the same RTP session are briefly mentioned, as they could have some benefits over the RTP- mixer model. The possibility to implement the solution in a wide range of existing RTP implementations made the RTP-mixer model be selected to be fully specified in this document. A capability exchange is specified so that it can be verified that a mixer and a participant can handle the multi-party coded real-time text stream using the RTP-mixer method. The capability is indicated by use of an SDP media attribute "rtt-mixer". The document updates RFC 4103 "RTP Payload for Text Conversation". A specification of how a mixer can format text for the case when the endpoint is not multi-party aware is also provided.},
}