%% You should probably cite rfc8292 instead of this I-D.
@techreport{ietf-webpush-vapid-03,
    number =    {draft-ietf-webpush-vapid-03},
    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-webpush-vapid/03/},
    author =    {Martin Thomson and Peter Beverloo},
    title =     {{Voluntary Application Server Identification (VAPID) for Web Push}},
    pagetotal = 14,
    year =      2017,
    month =     jun,
    day =       18,
    abstract =  {An application server can use the method described to voluntarily identify itself to a push service. This identification information can be used by the push service to attribute requests that are made by the same application server to a single entity. An application server can include additional information that the operator of a push service can use to contact the operator of the application server. This identification information can be used to restrict the use of a push subscription a single application server.},
}