1. J. W. Perry, S. Barlow, J. E. Ehrlich, et al., Nonlinear Opt. 21, 225 (1999).
2. P. N. Prasad, G. S. He, M. P. Joshi, et al., Nonlinear Opt. 21, 39 (1999).
3. V. V. Danilov, Yu. T. Mazyrenko, and S. I. Vorontzova, Opt. Commun. 9, 283 (1973).
4. V. V. Danilov, G. V. Klimusheva, L. I. Zagainova, and A. I. Khrebtov, Khim. Fiz. 8, 214 (1989).
5. V. V. Danilov, Yu. T. Mazurenko, and D. A. Savel’ev, Opt. Spektrosk. 57, 748 (1984) [Opt. Spectrosc. 57, 455 (1984)].