1. Hartley, R. V.: Bell Syst. Techn. J. 7, 535 (1928)
2. Shannon, C. E.: Bell Syst. Techn. J. 27, 379 (1948)
3. Weaver, W., Shannon, C. E.: The Mathematical Theory of Communication ( Univ. of Illinois Press, Urbana 1949 )
4. McMillan, B.: Ann. Math. Stat. 24, 196 (1953)
5. Feinstein, A.: Foundations of Information Theory ( McGraw-Hill, New York 1958 )