1. C.E. Shannon, Bell System Tech. Jour. 27, 623 (1948), and Ref. in Key Papers in the Development of Information Theory ( Part II ), edited by D. Slepian (I.E.E.E. Press, 1973 ).
2. R. Jodoin and L. Mandel, J. Opt. Soc. Am. 61, 191 (1971).
3. B. Picinbono and M. Rousseau, Phys. Rev. Al, 635 (1970).
4. T. Berger, Rate Distortion Theory, A Mathematical Basis for Data Compression (Prentice-Hall, Inc., Englewood Cliffs, N.J., 1971 ).