1. Kocharyan, N.M., Yerevan State University, Scientific studies, 1940, vol. 12, p. 23.
2. Alikhanian, A.I., Alikhanov, A.I., and Nikitin, S.A., J. Phys., 1945, vol. 9, p. 175.
3. Alikhanian, A.I. and Alikhanov, A.I., J. Phys., 1945, vol. 9, p. 167.
4. Anderson, C.D. and Neddermeyer, S.H., Phys. Rev., 1937, vol. 51, p. 884.
5. Grigorov, N.L., Murzin, V.S., and Rapoport, I.D., ZhETF, 1958, vol. 7, p. 348.