Preface
Chapter 1. General Theory of Nonlinear Oscillations 
1. Asymptotic Method 
2. Resonance in Nonlinear Systems
3. Self-Excited Oscillations. Van der Pol’s Equation
4. Forced Oscillations
5. Parametrically-Excited Oscillations
Chapter 2. Interaction Between External and Parametric Excitations
1. The Interaction Between External and Parametric Excitations of the First Degree
2. The Interaction Between External and Parametric Excitations of the Second Degree 
3. The Interaction Between External and Parametric Excitations of the Third Degree
4. The Interaction Between Parametric Excitations of the First and Third Degrees
5. The Interaction Between Two Parametric Excitations of First and Second Degrees