@misc{rfc4661,
    series =    {Request for Comments},
    number =    4661,
    howpublished =  {RFC 4661},
    publisher = {RFC Editor},
    doi =       {10.17487/RFC4661},
    url =       {https://www.rfc-editor.org/info/rfc4661},
    author =    {Jose Costa-Requena and Hisham Khartabil and Eva Leppanen and Mikko Lonnfors},
    title =     {{An Extensible Markup Language (XML)-Based Format for Event Notification Filtering}},
    pagetotal = 24,
    year =      2006,
    month =     sep,
    abstract =  {The SIP event notification framework describes the usage of the Session Initiation Protocol (SIP) for subscriptions and notifications of changes to a state of a resource. The document does not describe a mechanism whereby filtering of event notification information can be achieved. Filtering is a mechanism for defining the preferred notification information to be delivered and for specifying triggers that cause that information to be delivered. In order to enable this, a format is needed to enable the subscriber to describe the state changes of a resource that cause notifications to be sent to it and what those notifications are to contain. This document presents a format in the form of an XML document. {[}STANDARDS-TRACK{]}},
}