1. ITU-T, Recommendation P.834: Methodology for the derivation of equipment impairment factors from instrumental models
2. ITU-T Recommendation P.862.2: Methods for objective and subjective assessment of quality. Wideband extension to recommendation P.862 for the assessment of wideband telephone networks and speech codecs, Nov 2007
3. ITU-T, Recommendation P.862.1: Mapping function for transforming P.862 raw result scores to MOS-LQO. In: International Telecommunication Union - Telecommunication Standardisation Sector (ITU-T), March 2005
4. ITU-T Recommendation P.862: Perceptual evaluation of speech quality(PESQ): an objective method for end-to-end speech quality assessment of narrow-band telephone networks and speech codecs, Feb 2001
5. Rix, A.W.: Comparison between subjective listening quality and P.862 PESQ score. White Paper, Sept 2003