%% You should probably cite draft-ietf-sieve-variables instead of this I-D.
@techreport{homme-sieve-variables-04,
    number =    {draft-homme-sieve-variables-04},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-homme-sieve-variables/04/},
    author =    {Kjetil Torgrim Homme},
    title =     {{Sieve -- Variables Extension}},
    pagetotal = 12,
    year =      2004,
    month =     sep,
    day =       15,
    abstract =  {In advanced filtering rule sets, it is useful to keep state or con­ figuration details across rules. This extension adds an action to store data in variables, an action to retrieve the current time, changes the interpolation of strings, and supplies a new test so that the value of a string can be examined.},
}