[1] Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); TISPAN; IP Multimedia Call Control Protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP) Stage 3 [3GPP TS 24.229 (Release 7), modified] (3GPP TS 24.403 version 7.3.0 Release 7) (2009-06-16 17:50:40 +09:00) http://www.etsi.org/deliver/etsi_ts/124400_124499/124403/07.03.00_60/ts_124403v070300p.pdf