ETSI EN 300 938-1999 Digital Cellular Telecommunications System (Phase 2+); Mobile Station - Base Station System (MS - BSS) Interface; Data Link (DL) Layer Specification GSM 04.06 Version 6.0.1 Release 1997
2000ETSI EN 300 938:2000 Digital Cellular Telecommunications System (Phase 2+); Mobile Station - Base Station System (MS - BSS) Interface; Data Link (DL) Layer Specification (GSM 04.06 Version 6.2.0 Release 1997)
1999ETSI EN 300 938-1999 Digital Cellular Telecommunications System (Phase 2+); Mobile Station - Base Station System (MS - BSS) Interface; Data Link (DL) Layer Specification GSM 04.06 Version 6.0.1 Release 1997