“On Application of Lyapunov and Yoshizawa’s Theorems on Stability, Asymptotic Stability, Boundaries and Periodicity of Solutions of Duffing’s Equation”, AJAS, vol. 2, no. 6, Dec. 2014, Accessed: Mar. 04, 2026. [Online]. Available: https://ajouronline.com/index.php/AJAS/article/view/2034