1. Jayant, N.S.: Waveform quantization and coding, (IEEE Press, New York 1976)
2. Papamichalis, P.E.: Practical approaches to speech coding, (Prentice-Hall Inc, Englewood Cliffs, New Jersey 1987)
3. O'shaughnessy, D.: Speech communication human and machine, (Addison-Wesley publishing Company, New York, New York 1987)