%% You should probably cite draft-ietf-roll-ccast instead of this I-D.
@techreport{bergmann-bier-ccast-02,
    number =    {draft-bergmann-bier-ccast-02},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-bergmann-bier-ccast/02/},
    author =    {Olaf Bergmann and Carsten Bormann and Stefanie Gerdes and Hao Chen},
    title =     {{Constrained-Cast: Source-Routed Multicast for RPL}},
    pagetotal = 9,
    year =      2016,
    month =     oct,
    day =       5,
    abstract =  {This specification defines a protocol for forwarding multicast traffic in a constrained node network employing the RPL routing protocol in non-storing mode.},
}