1. 1. M. Bissiri, G. Baldassari H.v.H., M. Capizzi, V.M. Fomin, V.N. Gladilin and O.C. Vreese // Phys. status solidi(b)224(3), p.639-642 (2001).
2. 2. V.A. Burdov // Fizika Tverdogo Tela43(6), p. 1110-1115 (2001) (in Russian).
3. 3. V.I. Boichuk, R.Yu. Kubay // Ibid.43(2), p. 226-232 (2001) (in Russian).
4. 4. M.V. Tkach // The 2-nd Ukrainian Scientific Conference for Physics of Semiconductors. Abstracts. V.1. Chernivtsi - Vyzhnytsya, 20-24 September, p. 5 (in Russian).
5. 5. M.V. Tkach, A.V. Makhanets', P.G. Zegrya // Fizika i Tekhnika Poluprovodnikov 36(5), p. 543-549 (2002) (in Russian).