I. I. Kovtun, “Fluctuations of forced vibrations in a medium with resistance”, Ukr. Mat. Zhurn., vol. 45, no. 1, pp. 132–135, Jan. 1993, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5792