1. Yu. A. Anan’ev, Optical Resonators and Laser Beams (Nauka, Moscow, 1990).
2. N. N. Rozanov, Opt. Spektrosk. 90, 311 (2001) [Opt. Spectrosc. 90, 266 (2001)].
3. N. N. Rozanov, Opt. Spektrosk. 90, 136 (2001) [Opt. Spectrosc. 90, 121 (2001)].
4. A. A. Kominskii, Laser Crystals (Nauka, Moscow, 1975).
5. E. Yablonovich, Phys. Rev. Lett. 58, 2059 (1987).