1. J. Gray, Animal Locomotion (Weidenfeld and Nicolson, London, 1968).
2. J. Lighthill, Mathematical Biofluiddynamics (SIAM, Philadelphia, 1975).
3. N. N. Bogolyubov and Yu. A. Mitropol’skii, Asymptotic Methods in Theory of Nonlinear Oscillations (Fizmatgiz, Moscow, 1963) [in Russian].
4. F. L. Chernous’ko, Dokl. Akad. Nauk 55(3), 138 (2010).
5. F. L. Chernousko, J. Optimiz. Theory Appl. 147(2), 278 (2010).