ETSI TS 122 091-2002 数字蜂窝通信系统(第2+阶段).全球移动通信系统(UMTS).显式呼叫转移(ECT)补充业务.第1阶段.3GPP TS 22.091(版本5.0.0,第5次发布)
Digital Cellular Telecommunications System (Phase 2+); Universal Mobile Telecommunications System (UMTS); Explicit Call Transfer (ECT) Supplementary Service; Stage 1 3GPP TS 22.091 Version 5.0.0 Release 5