%% You should probably cite rfc9209 instead of this I-D.
@techreport{ietf-httpbis-proxy-status-01,
    number =    {draft-ietf-httpbis-proxy-status-01},
    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-httpbis-proxy-status/01/},
    author =    {Mark Nottingham and Piotr Sikora},
    title =     {{The Proxy-Status HTTP Response Header Field}},
    pagetotal = 18,
    year =      2020,
    month =     mar,
    day =       2,
    abstract =  {This document defines the Proxy-Status HTTP header field to convey the details of intermediary handling of responses, including generated errors.},
}