1. M. Aihara, Phys. Rev. B,21, No. 6, 2051?2054 (1980); V. S. Kuz'min and A. P. Saiko, Dokl. Akad. Nauk BSSR,25, No. 9, 797?800 (1981).
2. V. S. Kuz'min and A. P. Saiko, Zh. Prikl. Spektrosk.,39, No. 1, 135?141 (1983).
3. A. M. Stoneham, Theory of Defects in Solids [Russian translation], Vol. 1, Mir, Moscow (1978).
4. I. B. Bersuker and V. Z. Polinger, Vibronic Interactions in Molecules and Crystals [in Russian], Nauka, Moscow (1983).
5. V. S. Kuz'min and A. P. Saiko, Abstracts of Reports at the All-Union Conference on the, Theory of Atoms and Atomic Spectra, Minsk (1983), p. 156.