1. S. G. Ovchinnikov, I. S. Edelman, V. V. Markov, and V. A. Seredkin, Fiz. Tverd. Tela 49, 854 (2007) [Phys. Solid State 49, 900 (2007)].
2. I. Edelman, S. Ovchinnikov, V. Markov, et al., Phys. B: Condens. Matter (2008, in press); DOI 10.1016/j.physb.2008.04.018.
3. S. N. Varnakov, A. A. Lepeshev, S. G. Ovchinnikov, et al., Prib. Tekh. Éksp. 47(6), 252 (2004) [Instrum. Exp. Tech. 47, 839 (2004)].
4. V. A. Shvets, E. V. Spesivtsev, and S. V. Rykhlitskii, Opt. Spektrosk. 97, 514 (2004) [Opt. Spectrosc. 97, 483 (2004)].