1. S. H. Strogatz, Nonlinear Dynamics and Chaos: With Applications to Physics, Biology, Chemistry, and Engineering, 2nd Ed., CRC Press, Boca Raton, 2018
2. W. A. Strauss, Partial Differential Equations: An introduction, 2nd Ed., Wiley, Hoboken, 2008
3. N. Bloembergen, Nonlinear Optics, Benjamin, New York, 1964
4. N. M. Krylov and N. N. Bogolyubov, Introduction to Non-Linear Mechanics, Princeton University Press, Princeton, 1947
5. R. T. Beyer, Nonlinear Acoustics, Naval Ship Systems Command, Washington, D.C., 1974