1. W. Heisenberg, Introduction to the Unified Field Theory of Elementary Particles, Wiley, New York (1967).
2. D. D. Ivanenko, Phys. Zs. Sowjetunion,13, 141 (1938).
3. D. D. Ivanenko and A. M. Brodskii, Dokl. Akad. Nauk SSSR,84, 683 (1952); Zh. Eksp. Teor. Fiz.,24, 384 (1953).
4. A. I. Naumov, Yad. Fiz.,7, 664 (1968); Vest. Mosk. Un-ta, Fizika, Astronomiya, No. 2, 41 (1968).
5. N. S. Demidova and A. I. Naumov, Vest. Mosk. Un-ta, Fizika, Astronomiya,11, No. 2, 215 (1970).