1. M. V. Khvingiya, A. M. Bagdaeva, D. T. Gabadze, et al., Oscillations and Stability of Elastic Systems of Machines and Instruments [in Russian], Metsnieraba, Tbilisi (1974).
2. S. L. Tsyfanskii and A. B. Oks, “Stabilization of oscillations of systems with a nonlinear restoring force,” Prikl. Mekh.,22, No. 10, 105–109 (1986).
3. G. Korn and T. Korn, Mathematical Handbook [Russian translation], Nauka, Moscow (1978).
4. R. Sh. Abiev, E. G. Aksenova, and G. M. Ostrovskii, “New concepts of pulsation resonance plant for liquid-phase systems,” Khim. Prom., No. 11, 764–766 (1994).