Nguyễn Đông Anh, and Nguyễn Minh Triết. “Extension of Dual Criterion to Periodic Vibrational Nonlinear Systems”. Journal of Technical Education Science 10, no. 3 (September 25, 2015): 3–8. Accessed April 7, 2026. https://www.jte.edu.vn/index.php/jte/article/view/570.