1. D. Ivanenko, Phys. Zs. Sowjetunion,13, 141 (1938).
2. W. Heisenberg, Introduction to the Unified Field Theory of Elementary particles [Russian translation], Mir, Moscow (1968).
3. D. Ivanenko, Acta. Phys. Acad. Sci. Hung.,32, 341 (1972).
4. A. I. Naumov, Nuovo Cimento Lett.,5, 1129 (1972).
5. D. Ivanenko and A. Brodskii, Dokl. Akad. Nauk SSSR,84, 683 (1952).