A. Y. Shvets, “Deterministic chaos of a spherical pendulum under limited excitation”, Ukr. Mat. Zhurn., vol. 59, no. 4, pp. 534–548, Apr. 2007, Accessed: Feb. 01, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3327