1. Carrier Grade Voice over IP;Collins,2003
2. Implementing Voice over IP;Khasnabish,2003
3. Perceptual QoS assessment technologies for VoIP;Takahashi;IEEE Communications Magazine,2004
4. ITU-T, Recommendation P.800—methods for subjective determination of transmission quality, International Telecommunication Union-Telecommunication Standardisation Sector (ITU-T), August 1996.
5. ITU-T, Recommendation P.800.1—mean opinion score (MOS) terminology, International Telecommunication Union-Telecommunication Standardisation Sector (ITU-T), March 2003.