1. R.W. Hamming: Coding and Information Theory (Prentice-Hall, Engle-wood Cliffs, NY 1980)
2. P. Beckmann: Probability in Communication Engineering (Harcourt Brace and World, New York 1967)
3. G.D. Forney: Concatenated Codes (MIT Press, Cambridge, MA 1966)
4. D.A. Huffman: Proc. IRE 40, 1098 (1952)
5. L. Gatlin: Information Theory and the Living System (Columbia University Press, New York 1972;