1. Proceedings of the International Conference “Vector Mesons and Electromagnetic Interactions” (JINR, Dubna, 1969).
2. A. Einstein, Collection of Scientific Works (Nauka, Moscow, 1966) [in Russian].
3. Elementary Particle and Compensating Fields, Ed. by D. D. Ivanenko (Mir, Moscow, 1964) [in Russian].
4. Quantum Theory of Gauge Fields, Ed. by N. P. Konopleva (Mir, Moscow, 1977) [in Russian].
5. R. P. Feynman, Rev. Mod. Phys. 20, 367–387 (1948).