Hung, Luu Xuan. “Approximate Analysis of Some Two-Degree-of-Freedom Nonlinear Random Systems by an Extension of Gaussian Equivalent Linearization”. <i>Vietnam Journal of Mechanics</i> 23, no. 2 (July 1, 2001): 95–109. Accessed December 6, 2025. https://vjs.ac.vn/vjmech/article/view/9943.