%% You should probably cite rfc7639 instead of this I-D.
@techreport{ietf-httpbis-tunnel-protocol-04,
    number =    {draft-ietf-httpbis-tunnel-protocol-04},
    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-tunnel-protocol/04/},
    author =    {Andrew Hutton and Justin Uberti and Martin Thomson},
    title =     {{The ALPN HTTP Header Field}},
    pagetotal = 7,
    year =      2015,
    month =     may,
    day =       20,
    abstract =  {This specification allows HTTP CONNECT requests to indicate what protocol will be used within the tunnel once established, using the ALPN header field.},
}