1. J.W.S. Rayleigh, The Theory of Sound, 2nd Edition, 1945 re-issue. Dover Publications, New York, 1877.
2. Stability and Oscillations of Elastic Systems; Paradoxes, Fallacies and New Concepts;Panovko,1965
3. Quenching of Self-Excited Vibrations;Tondl,1991
4. Nonlinear Oscillations;Nayfeh,1979
5. Applied Asymptotic Methods in Nonlinear Oscillations;Mitropolskii,1997