%% You should probably cite rfc7390 instead of this I-D.
@techreport{ietf-core-groupcomm-01,
    number =    {draft-ietf-core-groupcomm-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-ietf-core-groupcomm/01/},
    author =    {Akbar Rahman and Esko Dijk},
    title =     {{Group Communication for CoAP}},
    pagetotal = 34,
    year =      2012,
    month =     mar,
    day =       9,
    abstract =  {This is a working document intended to develop draft text for the CoAP protocol specification in the area of group communication. A solution based on IP multicast is proposed and detailed. Also, guidance is provided for deployment in various constrained network topologies.},
}