1. O. V. Klyavin, Fiz. Tverd. Tela (St. Petersburg) 35(3), 513 (1993) [Phys. Solid State 35 (3), 261 (1993)].
2. O. V. Klyavin, V. I. Nikolaev, L. V. Khabarin, Yu. M. Chernov, and V. V. Shpeĭzman, Fiz. Tverd. Tela (St. Petersburg) 45(12), 2187 (2003) [Phys. Solid State 45 (12), 2292 (2003)].
3. O. V. Klyavin, B. A. Mamyrin, L. V. Khabarin, and Yu.M. Chernov, Fiz. Tverd. Tela (St. Petersburg) 44(2), 291 (2002) [Phys. Solid State 44 (2), 302 (2002)].
4. O. V. Klyavin, B. A. Mamyrin, L. V. Khabarin, and Yu.M. Chernov, Fiz. Tverd. Tela (St. Petersburg) 47(5), 837 (2005) [Phys. Solid State 47 (5), 863 (2005)].
5. O. V. Klyavin, V. I. Nikolaev, B. I. Smirnov, L. V. Khabarin, Yu. M. Chernov, and V. V. Shpeĭzman, Fiz. Tverd. Tela (St. Petersburg) 51(3), 473 (2009) [Phys. Solid State 51 (3), 503 (2009)].