1. Liu Zeng-Rong. The Melnikov method in researching chaos[A]. In: Guo Zhong-Heng ed. Modern Mathematics and Mechanics [C]. Beijing, Peking University Press, 1987, 269–290 (in Chinese).
2. Wiggins S. Global Bifurcations and Chaos [M]. Berlin, Springer-Verlag, 1988.
3. Holmes P J. Averaging and chaotic motions in forced oscillations[J]. SIAM J. Appl. Math., 1980, 38(1): 65–80; 1980, 40(1): 167–168.
4. Jiang Ji-Fa, Liu Zeng-Rong. Subharmonic bifurcation and horseshoe in a non-Hamiltonian system [J]. Math. Appl. Sinica, 1987, 10(4): 504–508 (in Chinese).
5. Chen Li-Qun, Liu Yan-Zhu. Chaos in quasiperiodically perturbed planar non-Hamiltonian integrable systems [J]. J. Shanghai Jiaotong Univ., 1996, 30(11): 28–31 (in Chinese)