1. L. D. Landau and E. M. Lifshitz, Course of Theoretical Physics, Vol. 8: Electrodynamics of Continuous Media (Nauka, Moscow, 1982, Pergamon, New York, 1984).
2. R. W. Boyd, Nonlinear Optics (Academics, Rochester, New York, 2008).
3. G. G. Gurzadyan, V. G. Dmitriev, and D. N. Nikogosyan, Nonlinear Optical Crystals. Properties and Application in Quantum Electronics (Radio i Svyaz’, Moscow, 1991) [in Russian].
4. K. Reimann, Rep. Prog. Phys. 70, 1597 (2007).
5. S. B. Bodrov, M. I. Bakunov, and M. Hangyo, J. Appl. Phys. 104, 093105 (2008).