1. B. Schneider, Phys. Status Solidi B 51(1), 325 (1972).
2. S. N. Bajpai, I. Rattan, and N. C. Srivastava, J. Appl. Phys. 50(4), 2887 (1979).
3. R. A. Lemons and B. A. Auld, J. Appl. Phys. 52(12), 7360 (1981).
4. O. A. Chivileva, A. G. Gurevich, and L. M. Émiryan, Fiz. Tverd. Tela (Leningrad) 29(1), 110 (1987) [Sov. Phys. Solid State 29, 61 (1987)].
5. I. V. Zavislyak, V. M. Talalaevskii, and L. V. Chevnyuk, Fiz. Tverd. Tela (Leningrad) 31(5), 319 (1989) [Sov. Phys. Solid State 31, 906 (1989)].