Dao, Nguyen Van, Nguyen Van Dinh, and Tran Kim Chi. “Van Der Pol’s Oscillator under the Parametric and Forced Excitations”. Vietnam Journal of Mechanics 29, no. 3 (September 22, 2007): 207–219. Accessed December 5, 2025. https://vjs.ac.vn/vjmech/article/view/5533.