1. Some Problems in the Theory of Nonlinear Oscillation;Malkin,1956
2. Asymptotic Methods in the Theory of Nonlinear Osillations;Bogoliubov,1961
3. Stability Theory of Motion;Malkin,1968
4. Stability of Motion;Cetaiev,1965
5. Introduction to the Stability of Motion Theory;Merkin,1976