1. Fock V. A.: Z. Phys.61 (1930), 126.
2. Hartree D. R.: Proc. Cambr. Phil. Soc.24 (1928), 89, 111.
3. Elsasser W. M.: J. phys. et radium5 (1933), 549;5 (1934), 389, 635.
4. Gillet V.:in Proc. of 11. Summer Meeting of Nuclear Physicists, Herceg Novi 1966. Vol. I. (Ed. by L. Šips) Federal Nuclear Energy Commission of Yugoslavia, Beograd 1966, 1.
5. Giraud B.:in Proc. of 11. Summer Meeting of Nuclear Physicists, Herceg Novi 1966. Vol. II. (Ed. by L. Šips.) Federal Nuclear Energy Commission of Yugoslavia, Beograd 1966, 297.