1. ?Enrico Fermi? International School of Physics;G. R. Burbidge,1966
2. Falla, D. and Evans, A.: 1975,Astrophys. Space Sci. 37, 11.
3. Ginzburg, V. L. and Syrovatskii, S. I.: 1964,The Origin of Cosmic Rays, Pergamon Press, Oxford.
4. Khachikian, E. Ye. and Weedman, D. W.: 1971,Astrofizika 7, 389.
5. Neugebauer, G.: 1978,Physica Scripta 17, 149.