ETSI TS 129 018-2003 数字蜂窝通信系统(第2+代);全球移动通信系统(UMTS);通用分组无线业务(GPRS);服务GPRS支持节点(SGSN).拜访位置登记处(VLR);Gs接口第3层规范(3GPP TS)
Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); General Packet Radio Service (GPRS); Serving GPRS Support Node (SGSN) - Visitors Location Register (VLR); Gs interface layer 3 specification 3GPP TS