1. Asymptotic Methods in the Theory of Non-linear Oscillations;Bogolyubov,1974
2. Nichtlineare Mechanik;Kauderer,1958
3. Schwingungen;Magnus,1976
4. Oscillations and the Stability of Periodic Motion;Chechurin,1983
5. The Stability and Oscillations of Elastic Systems. Modern Concepts, Paradoxes and Errors;Panovko,1987