[1] RFC 4480 - RPID: Rich Presence Extensions to the Presence Information Data Format (PIDF) (2018-02-18 21:52:25 +09:00) https://tools.ietf.org/html/rfc4480#section-3.13

[2] (2017-11-30 21:47:54 +09:00) https://www.gsma.com/futurenetworks/wp-content/uploads/2017/11/FNW.11_v1.0.pdf#page=8

[3] 関連: 時差の記述