1. 1. A.I. Kitaigorodskii, Molecular Crystals and Molecules (Academic Press, New York, 1973).
2. 2. M.S. Brodin, S.V. Marisova, and A.F. Prikhot'ko, in Excitons in Molecular Crystals (Nauka, Moscow, 1973), p. 50 (in Russian).
3. 3. J.M. Turlet and M.P. Philpott, J. Chem. Phys. 62, 4260 (1975).
4. 4. D.D. Kolendritskii, M.V. Kurik, and Yu.P. Piryatinskii, Opt. Spektrosk. 44, 281 (1978).
5. 5. D.D. Kolendritskii, M.V. Kurik, and Yu.P. Piryatinskii, Phys. Status Solidi B 91, 741 (1979).