Scarpello, Giovanni Mingari, and Daniele Ritelli. “Closed Form Integration of the Rotating Plane Pendulum Nonlinear Equation”. Tamkang Journal of Mathematics 34, no. 4 (December 31, 2003): 327–350. Accessed April 25, 2024. https://journals.math.tku.edu.tw/index.php/TKJM/article/view/235.