1. Andronov, Vitt, A.A. and Khaikin, S.E. (1966) Theory of oscillators, Pergamon Press.
2. Blaquiere, Nonlinear system analysis, Academic Press.
3. Bogolioubov and Mitropolski (1962) Les méthodes asymptotiques en théorie des oscillations non linéarires, Gauthiers Villars.
4. Chaleat, R. and Hagg, J. (1960) Problémes de Chronométrie et de théorie générale des oscillations, Gauthier Villars.
5. Chua, L.O. (1969) Introduction to nonlinear network theory, McGraw Hill.