Khashan, M. Motawi, Muhammed I. Syam, and A.K. Alomari. “Numerical Solution of Cubic Free Undamped Duffing Oscillator Equation Using Continuous Implicit Hybrid Method”. Italian Journal of Pure and Applied Mathematics 42 (July 30, 2019): 588–597. Accessed October 27, 2026. https://journals.uniurb.it/index.php/ijpam/article/view/7208.