1. Akhmanov S. A., Chirkin A. S.: Statisticheskie yavleniya v nelineinoy optike. Moskovskii Universitet, Moscow, 1971.
2. Andreev R. B., Volosov V. D.: Kvantovaya Elektron. Moskva; (1974) 1355.
3. Schubert M., Wilhelmi B.:in Progress in Optics, Vol. 17 (ed. E. Wolf). North-Holland, Amsterdam, 1980, p. 163.
4. Peřina J.:in Progress in Optics, Vol. 18 (ed. E. Wolf). North-Holland, Amsterdam, 1980, p. 127.
5. Kielich S.: Molekulyarnaya nelineinaya optika. Nauka, Moscow, 1981.