%% You should probably cite rfc7852 instead of this I-D.
@techreport{ietf-ecrit-additional-data-30,
    number =    {draft-ietf-ecrit-additional-data-30},
    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-ecrit-additional-data/30/},
    author =    {Randall Gellens and Brian Rosen and Hannes Tschofenig and Roger Marshall and James Winterbottom},
    title =     {{Additional Data Related to an Emergency Call}},
    pagetotal = 109,
    year =      2015,
    month =     jun,
    day =       1,
    abstract =  {When an emergency call is sent to a Public Safety Answering Point (PSAP), the device that sends it, as well as any application service provider in the path of the call, or access network provider through which the call originated has information about the call, the caller or the location which might be helpful for the PSAP to have in handling the emergency. This document describes data structures and a mechanism to convey such data to the PSAP. The intent is that every emergency call carry the information described here using the mechanisms described here. The mechanism uses a Uniform Resource Identifier (URI), which may point to either an external resource or an object in the body of the SIP message. The mechanism thus allows the data to be passed by reference (when the URI points to an external resource) or by value (when it points into the body of the message). This follows the tradition of prior emergency services standardization work where data can be conveyed by value within the call signaling (i.e., in body of the SIP message) and also by reference.},
}