1. M. V. Kuz’min, M. V. Loginov, and M. A. Mittsev, Fiz. Tverd. Tela (St. Petersburg) 51(4), 795 (2009) [Phys. Solid State 51 (4), 841 (2009)].
2. M. V. Kuz’min and M. A. Mittsev, Fiz. Tverd. Tela (St. Petersburg) 52(3), 577 (2010) [Phys. Solid State 52 (3), 625 (2010)].
3. M. V. Kuz’min and M. A. Mittsev, Fiz. Tverd. Tela (St. Petersburg) 52(6), 1202 (2010) [Phys. Solid State 52 (6), 1279 (2010)].
4. M. V. Kuz’min and M. A. Mittsev, Fiz. Tverd. Tela (St. Petersburg) 53(3), 569 (2011) [Phys. Solid State 53 (3), 612 (2011)].
5. D. V. Buturovich, M. V. Kuz’min, M. V. Loginov, and M. A. Mittsev, Fiz. Tverd. Tela (St. Petersburg) 50(1), 168 (2008) [Phys. Solid State 50 (1), 173 (2008)].