1. Mkrtchyan, A.R., Navasardian, M.A., and Mirzoyan, V.K., Pis’ma v ZhETF, 1982, vol. 8, p. 677.
2. Mkrtchyan, A.R., Gabrielyan, R.G., Aslanyan, A.A., et al., Izvestiya Akademii Nauk Arm. SSR, Fizika, 1986, vol. 21, p. 297.
3. Mkrtchyan, A.R., Mkrtchyan, A.H., Kocharyan, V.R., Movsisyan, A.E., Dabagov, S.B., and Potylicyn, A.P., J. Contemp. Phys. (Armenian Ac. Sci.), 2013, vol. 48, p. 141.
4. Kocharyan, V.R., Aleksanyan, R.Sh., and Truni, K.G. J. Contemp. Phys. (Armenian Ac. Sci.), 2010, vol. 45, p. 190.
5. Mkrtchyan, A.R., Navasardian, M.A., and Gabrielyan, R.G., Pis’ma v ZhETF, 1985, vol. 11, p. 1354.