1. I. P. Ipatova, V. A. Shchukin, V. G. Malyshkin, A. Yu. Maslov, and E. Anastassakis, Solid State Commun. 78, 19 (1991).
2. V. A. Shchukin, in Proc. of the 23rd Intern. Conf. on Physics of Semiconductors, ed. by M. Scheffler and R. Zimmermann (World Sci., Singapore, 1996), p. 1261.
3. N. N. Ledentsov, in Proc. of the 23rd Intern. Conf. on Physics of Semiconductors, ed. by M. Scheffler and R. Zimmermann (World Sci., Singapore, 1996), p. 19.
4. R. Nötzel, Semicond. Sci. Technol. 11, 1365 (1996).
5. N. T. Bagraev, W. Gehlhoff, L. E. Klyachkin, A. Naeser, and S. A. Rykov, Def. Dif. Forum, 143–147, 1003 (1997).