1. 3GPP:TS 46.010: Full rate speech encoding, Third Generation Partnership Project (3GPP), 2002.
2. 3GPP:TS 46.051: GSM Enhanced full rate speech processing functions: General description, Third Generation Partnership Project (3GPP), 2002.
3. 3GPP : TS 46.090: AMR speech codec: Transcoding functions, Third Generation Partnership Project (3GPP), 2002.
4. 3GPP TS 26.077: Technical specification group services and system aspects; Minimum performance requirements for noise suppresser; Application to the adaptive multi-rate (AMR) speech encoder, Third Generation Partnership Project (3GPP), 2003.
5. 70/157/EWG: Richtlinie des Rates zur Angleichung der Rechtsvorschriften der Mitgliedsstaaten über den zulässigen Geräuschpegel und die Auspuffvorrichtung von Kfz, 6. Feb. 1970 (in German).