1. P. S. Landa, Nonlinear Oscillations and Waves (Nauka, Moscow, 1997) [in Russian].
2. A. Scott, Active and Nonlinear Wave Propagation in Electronics (Wiley, New York, 1970; Sovetskoe Radio, Moscow, 1977).
3. A. N. Volobuev, V. N. Zhukov, E. L. Ovchinnikov, et al., Biofizika 36, 546 (1991).
4. A. N. Volobuev, E. L. Ovchinnikov, and D. A. Trufanov, Biofizika 45, 89 (2000).
5. L. A. Vaĭshteĭn, Electromagnetic Waves (Nauka, Moscow, 1969) [in Russian].