1. Some Problems of Rotor Dynamics;Tondl,1965
2. Resonance Oscillations in Mechanical Systems;Evan-Iwanowski,1976
3. Non-linear Oscillations;Nayfeh,1979
4. The response of one-degree-of-freedom system with quadratic and cubic non-linearities to sub-harmonic excitation;Nayfeh;Journal of Sound and Vibration,1983
5. The response of a single-degree-of freedom system with quadratic and cubic non-linearities to a fundamental parametric resonance;Zavodney;Journal of Sound and Vibration,1988