1. S. Weinberg, Phys. Rev.,D8, No. 12, 4482?4498 (1973).
2. W. Heisenberg, Introduction to the Unified Field Theory of Elementary Particles, Interscience, London (1966).
3. S. S. Sannikov, Dokl. Akad. Nauk SSSR,209, No. 2, 324?327 (1973).
4. S. S. Sannikov, Teor. Mat. Fiz.,34, No. 1, 34?47 (1978).
5. V. I. Arnol'd, Mathematical Methods of Classical Mechanics [in Russian], Nauka, Moscow (1979).