1. T. Regge, Nuovo Cimento,10, 544 (1958).
2. Ya. A. Smorodinskii and L. A. Shelepin, Usp. Fiz. Nauk.,106, 3 (1972).
3. S. M. R. Ansary, J. Math. Phys.,9, 1295 (1968);9, 1299 (1968).
4. I. M. Gel'fand, R. A. Minlos, and Z. Ya. Shapiro, Representations of the Rotation and Lorentz Groups and Their Applications, Pergamon Press, Oxford (1963); N. Ya. Vilenkin, Special Functions and the Theory of Group Representations, AMS Providence, Rhode Island (1968).
5. A. P. Yutsis and A. A. Bandzaitis, Theory of Angular Momentum in Quantum Mechanics [in Russian], Mintis Vil'nyus (1965).