%% You should probably cite draft-ietf-6man-ipv6only-flag instead of this I-D.
@techreport{hinden-ipv4flag-04,
    number =    {draft-hinden-ipv4flag-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-hinden-ipv4flag/04/},
    author =    {Bob Hinden and Brian E. Carpenter},
    title =     {{IPv6 Router Advertisement IPv6-Only Flag}},
    pagetotal = 9,
    year =      2018,
    month =     apr,
    day =       16,
    abstract =  {This document specifies a Router Advertisement Flag to indicate to hosts that the administrator has configured the router to advertise that the link is IPv6-Only. This document updates RFC5175.},
}