S. N. Bak and A. A. Pankov, “On the dynamical equations of a system of linearly coupled nonlinear oscillators”, Ukr. Mat. Zhurn., vol. 58, no. 6, pp. 723–729, Jun. 2006, Accessed: Feb. 16, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3490