ETSI PRETS 300 950-1999 数字蜂窝通信系统(第2+阶段).移动无线接口第3层补充业务规范.格式和编码.第4版.GSM 04.80(版本5.3.0,1996年发布)
Digital Cellular Telecommunications System (Phase 2+); Mobile Radio Interface Layer 3 Supplementary Services Specification; Formats and Coding Fourth Edition; GSM 04.80 Version 5.3.0 Release 1996