1. R. I. Personov and V. V. Solodunov, Opt. Spektrosk.,23, 590 (1967).
2. G. M. Svishchev, Opt. Spektrosk.,16, 364 (1964).
3. R. I. Personov and V. V. Solodunov, Fiz. Tverd. Tela,10, 1848 (1968);11, 2890 (1969).
4. E. I. Al'shits, É. D. Godyaev, and R. I. Personov, Fiz. Tverd. Tela,14, 1605 (1972); Isv. Akad. Nauk SSSR, Ser. Fiz.,36, 1117 (1972).
5. J. L. Richards and S. A. Rice, J. Chem. Phys.,54, 2014 (1971).