%% You should probably cite draft-ietf-httpbis-targeted-cache-control instead of this I-D.
@techreport{cdn-control-header-01,
    number =    {draft-cdn-control-header-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-cdn-control-header/01/},
    author =    {Stephen Ludin and Mark Nottingham and Yuchen Wu},
    title =     {{Targeted HTTP Response Header Fields for Cache Control}},
    pagetotal = 8,
    year =      2021,
    month =     mar,
    day =       17,
    abstract =  {This specification defines a convention for HTTP response header fields that allow directives controlling caching to be targeted at specific caches or classes of caches. It also defines one such header field, targeted at Content Delivery Network (CDN) caches.},
}