%% You should probably cite rfc7390 instead of this I-D.
@techreport{ietf-core-groupcomm-02,
    number =    {draft-ietf-core-groupcomm-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-ietf-core-groupcomm/02/},
    author =    {Akbar Rahman and Esko Dijk},
    title =     {{Group Communication for CoAP}},
    pagetotal = 25,
    year =      2012,
    month =     jul,
    day =       10,
    abstract =  {CoAP is a RESTful transfer protocol for constrained devices. It is anticipated that constrained devices will often naturally operate in groups (e.g. in a building automation scenario all lights in a given room may need to be switched on/off as a group). This document defines how the CoAP protocol should be used in a group communication context. An approach for using CoAP on top of IP multicast is detailed for both constrained and un-constrained networks. Also, various use causes and corresponding protocol flows are provided to illustrate important concepts. Finally, guidance is provided for deployment in various network topologies.},
}