1. Arnold, V. I. (1964). Instability of dynamical systems with many degrees of freedom,Sov. Math. Dokl. 5, 581–585.
2. Arnold, V. I. (1973).Ordinary Differential Equations, MIT Press, Cambridge, MA, and London, England.
3. Arnold, V. I. (1988).Dynamical Systems III, Encyclopedia of Mathematical Sciences, Vol. 3, Springer-Verlag, Berlin, Heidelberg, New York, London, Paris, Tokyo.
4. Bishop, A. R., Flesch, R., Forest, M. G., McLaughlin, D. W., and Overman, E. A. (1990). Correlations between chaos in a perturbed sine-Gordon equation and a truncated model system.SIAM J. Math. Anal. 21, 1511–1536.
5. Chow, S. N., Hale, J., and Mallet-Paret, J. (1980). An example of bifurcation to homoclinic orbits.J. Diff. Eqs. 37, 351–373.