%% You should probably cite draft-ietf-6man-ipv6only-flag instead of this I-D.
@techreport{hinden-ipv4flag-01,
    number =    {draft-hinden-ipv4flag-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-hinden-ipv4flag/01/},
    author =    {Bob Hinden and Brian E. Carpenter},
    title =     {{IPv6 Router Advertisement IPv4 Unavailable Flag}},
    pagetotal = 8,
    year =      ** No value found for 'doc.pub_date.year' **,
    month =     ** No value found for 'doc.pub_date' **,
    day =       ** No value found for 'doc.pub_date.day' **,
    abstract =  {This document specifies a Router Advertisement Flag to indicate that there is no IPv4 service on the advertising default IPv6 router. This document updates RFC5175.},
}