%% You should probably cite draft-ietf-geopriv-uncertainty instead of this I-D.
@techreport{thomson-geopriv-confidence-04,
    number =    {draft-thomson-geopriv-confidence-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-thomson-geopriv-confidence/04/},
    author =    {Martin Thomson},
    title =     {{Expressing Confidence in a Location Object}},
    pagetotal = 8,
    year =      2013,
    month =     aug,
    day =       27,
    abstract =  {A confidence element is described that expresses the estimated probability that the associated location information is correct. This element conveys information that might otherwise be lost about the probability distribution represented by a region of uncertainty.},
}