1. S. Weinberg:Phys. Rev.,166, 1568 (1967).
2. S. P. Rosen:Phys. Rev.,188, 2542 (1969).
3. S. P. Rosen:Phys. Rev. D,1, 3392 (1970).
4. P. Carruthers:Introduction to Unitary Symmetry (New York, 1966), p. 72.
5. M. Moshinsky andP. Kramer:Group Theory and its Applications, edited byE. M. Loebl (New York, 1968), p. 339.