Dao, Nguyen Van, Nguyen Van Dinh, and Tran Kim Chi. “Van Der Pol’s Oscillator under the Parametric and Forced Excitations”. <i>Vietnam Journal of Mechanics</i> 29, no. 3 (September 22, 2007): 207–219. Accessed November 8, 2025. https://vjmech.vast.vn/vjmech/article/view/5533.