%% You should probably cite draft-ietf-dhc-v6only instead of this I-D.
@techreport{link-dhc-v6only-01,
    number =    {draft-link-dhc-v6only-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-link-dhc-v6only/01/},
    author =    {Lorenzo Colitti and Jen Linkova and Michael Richardson and Tomek Mrugalski},
    title =     {{IPv6-Only-Preferred Option for DHCP}},
    pagetotal = 10,
    year =      2019,
    month =     dec,
    day =       9,
    abstract =  {This document specifies a DHCP option to indicate that a host supports an IPv6-only mode and willing to forgo obtaining an IPv4 address if the network provides IPv6 connectivity.},
}