ETSI TR 101 085-1997 数字蜂窝通信系统(第2阶段).GSM增强型全速率(EFR)语音编解码器的性能特征(版本4.0.0).GSM 06.54 (版本4.0.0)
Digital Cellular Telecommunications System (Phase 2); Performance Characterization of the GSM Enhanced Full Rate (EFR) Speech Codec V4.0.0; GSM 06.55 Version 4.0.0