1. S. A. Agafonov, “Andronov-Hopf bifurcation in the motion of a rotatry shaft,” Izv. Vuzov, Mashinostr., No. 1, 22–25 (1989).
2. S. A. Agafonov, “Constructing a limit cycle for a rotary shaft,” Izv. Vuzov, Mashinostr., No. 12, 51–53 (1989).
3. V. I. Arnol'd, Catastrophe Theory [in Russian], Nauka, Moscow (1990).
4. B. S. Bardin and A. P. Markeev, “Stability of the equilibrium of a pendulum with vertically oscillating point of suspension,” Prikl. Mat. Mekh., 59, No.6, 922–929 (1995).
5. N. N. Bautin, Behavior of Dynamic Systems near the Stability Boundaries [in Russian], Nauka, Moscow (1984).