ETSI TS 122 091-2005 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6.0.0,第6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 6.0.0 Release 6