1. A. A. Andronov, A. A. Vitt, and S. E. Khaikin, Theory of Oscillations [in Russian], Nauka, Moscow (1981).
2. V. I. Arnol’d, V. V. Kozlov, and A. I. Neishtadt, “Mathematical aspects of classical and celestial mechanics,” in: Modern Problems of Mathematics: Fundamental Research Areas [in Russian], Vol. 3, VINITI AN SSSR, Moscow (1985).
3. N. N. Bogolyubov and Y. A. Mitropolsky, Asymptotic Methods in the Theory of Nonlinear Oscillations, Gordon and Breach, New York (1962).
4. D. M. Klimov, “One type of self-oscillations in a system with dry friction,” Mekh. Tverd. Tela, No. 3, 6–12 (2003).
5. N. V. Nikitina and I. V. Tsidylo, “Vibrations of a gyroscopic meridian-plane sensor in a fluid suspension,” Int. Appl. Mech., 30, No.1, 77–83 (1994).