1. B. Z. Katsenelenbaum, Theory of Irregular Waveguides with Slowly Changing Parameters (Akad. Nauk SSSR, Moscow, 1961; PN, 1979).
2. A. W. Snyder and J. D. Love, Optical Waveguide Theory (Chapman and Hall, New York, 1984; Radio Svyaz’, Moscow, 1987).
3. R. J. Black and L. Gagnon, Optical Waveguide Modes: Polarization, Coupling and Symmetry (McGraw-Hill Education, New York, 2010).
4. A. S. Raevskii and S. B. Raevskii, Complex Waves (Radiotekhnika, Moscow, 2010) [in Russian].
5. V. A. Andreev and A. V. Burdin, Multimode Optic Fibers. Theory and Applications of High Speed Communication Networks (Radio Svyaz’, Moscow, 2004) [in Russian].