ETSI EN 301 918-2003 专用综合业务网(PISN).规范,功能模型和信息流.单步呼叫转移补充业务(版本1.1.1).ISO/IEC 19459(2001),修正本
Private Integrated Services Network (PISN); Specification, functional model and information flows; Single step call transfer supplementary service (V1.1.1; ISO/IEC 19459 (2001) modified)