1. E. P. Wigner, Group Theory and its Application to the Quantum Mechanics of Atomic Spectra, Academic Press New York (1959).
2. G. Racah, Phys. Rev.,62, 438 (1942);63, 367 (1943);76, 1352 (1949); Group Theory and Spectroscopy, Princeton (1951).
3. T. Regge, Nuovo Cimento,10, 544 (1958).
4. L. A. Shelepin, Tr. Fiz. Inst. Akad. Nauk SSSR,70, 3 (1973).
5. D. A. Varshalovich, A. N. Moskalev, and V. K. Khersonskii, Quantum Theory of Angular Momenta [in Russian] Nauka (1975).