1. On a new type of dynamical stability;Stephenson;Mem. Proc. Manch. Lit. Philos. Soc.,1908
2. Dynamic stability of the pendulum with vibrating suspension point;Kapitza;Sov. Phys. JETP,1951
3. A pendulum theorem;Acheson;Proc. R. Soc. Lond., Ser. A,1993
4. Mechanical Vibrations;den Hartog,1956
5. Course of Theoretical Physics. Vol. 1;Landau,1976