1. Alikhanov, A.I., Alikhanyan, A.I., Nemenov, L. and Kocharyan, N.M.: 1944, Phys. USSR8, 63.
2. Alikhanov, A.I. and Alikhanyan, A.I.: 1945, JETF
15, 145.
3. Anderson, C.D.: 1933, Phys. Rev. 43, 491.
4. Anderson, C.D., Millikan, R. and Pickering, W.: 1934, Phys. Rev.
45, 352.
5. Aseikin, V. S. et al.: 1974, Izv. AN SSSR, Ser. Phys. 38, 998.