1. V. V. Golubkov and V. A. Tsekhomskiĭ, Fiz. Khim. Stekla 8, 416 (1982).
2. V. V. Golubkov and V. A. Tsekhomskiĭ, Fiz. Khim. Stekla 12, 206 (1986).
3. A. I. Ekimov, A. A. Onushchenko, A. G. Plyukhin, and Al. L. Éfros, Zh. Éksp. Teor. Fiz. 88, 1490 (1985) [Sov. Phys. JETP 61 (4), 891 (1985)].
4. A. I. Ekimov, Phys. Scr. 39, 217 (1991).
5. V. M. Zalkin, Zh. Fiz. Khim. 79(4), 763 (2005) [Russ. J. Phys. Chem. 79 (4), 655 (2005)].