%% You should probably cite rfc6910 instead of this I-D.
@techreport{ietf-bliss-call-completion-18,
    number =    {draft-ietf-bliss-call-completion-18},
    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-bliss-call-completion/18/},
    author =    {Dale R. Worley and Martin Huelsemann and Roland Jesske and Denis Alexeitsev},
    title =     {{Call Completion for Session Initiation Protocol (SIP)}},
    pagetotal = 37,
    year =      2012,
    month =     nov,
    day =       30,
    abstract =  {The call completion feature defined in this specification allows the caller of a failed call to be notified when the callee becomes available to receive a call. For the realization of a basic solution without queuing, this document references the usage of the dialog event package (RFC 4235) that is described as 'automatic redial' in the SIP Service Examples (RFC 5359). For the realization of a more comprehensive solution with queuing, this document introduces an architecture for implementing these features in the Session Initiation Protocol where "call completion" implementations associated with the caller's and callee's endpoints cooperate to place the caller's request for call completion into a queue at the callee's endpoint, and when a caller's request is ready to be serviced, re-attempt of the original, failed call is made. The architecture is designed to interoperate well with existing call- completion solutions in other networks.},
}