# Talk:Van der Pol oscillator

From Scholarpedia

Missing reference is very important:
Cartwright M. L. & Littlewood J. E. [1945] On nonlinear differential equations of the second order, I: The
equation y*+k(1+y^2)y'+y = b\lambda k cos(�t+a), k large, Lond. Math. Soc. 20, 180-189.*
Their conclusion: chaos is a typical dynamical state.

The route to chaos: Van der Pol & Van der Mark -> Cartwright & Littlewood -> Levinson -> Smale -> horseshoe.

(reply)
I added the above reference.
I will revise the article later.