1. Yu. I. Golovin, Fiz. Tverd. Tela (St. Petersburg) 46(5), 769 (2004) [Phys. Solid State 46 (5), 789 (2004)].
2. O. I. Datsko and V. I. Alekseenko, Fiz. Tverd. Tela (St. Petersburg) 39(7), 1234 (1997) [Phys. Solid State 39 (7), 1094 (1997)].
3. J. V. Osinskaya and A. V. Pokoev, Diffus. Defect Data, Pt. A 216–217, 157 (2003).
4. A. E. Smirnov, N. N. Bekkauer, and A. É. Voloshin, Fiz. Tverd. Tela (St. Petersburg) 47(7), 1253 (2005) [Phys. Solid State 47 (7), 1296 (2005)].
5. R. B. Morgunov, Usp. Fiz. Nauk 174(2), 131 (2004) [Phys.—Usp. 47 (2), 125 (2004)].