1. Babakov, N.A., Voronov, A.A., Voronova, A.A., et al. (eds.): Theory of automatic control: Textbook. for universities on spec. “Automation and telemechanics”. Part I. Theory of linear automatic control systems. Higher school, Moscow, Russia (1986). (in Russian)
2. Encyclopedia of mechanical engineering. https://mash-xxl.info/info/174754/
3. Rubanik, V.P.: Oscillations of Quasilinear Systems with Time Lag. Nauka, Moscow (1969). (in Russian)
4. Zhirnov, B.M.: Single-frequency resonant vibrations of a frictional self-oscillating system with a delay under an external perturbation. Appl. Mech. 14(9), 102–109 (1978). (in Russian)
5. Abdiev, F.K.: Delayed self-oscillations of a system with an imperfect energy source. Izv. AN AzSSR Ser. Phis.-Tekh. Math. Nauk. (4), 134–139 (1983). (in Russian)