1. Araki, H. and Yanase, M. (1961).Physical Review,120, 622.
2. Band, W. and Park, J. (1972).International Journal of Theoretical Physics, Vol. 6, No. 1, p. 9.
3. d'Espagnat, B. (1965).Conceptions de la Physique Contemporaine. Hermann, Paris.
4. Fine, A. (1970).Physical Review,D2, 2783.
5. Jammer, M. (1966).The Conceptual Development of the Quantum Theory. McGraw-Hill, New York.