V. M. Evtukhov and N. S. Vasileva, “Conditions of oscillatory or nonoscillatory nature of solutions for a class of second-order semilinear differential equations”, Ukr. Mat. Zhurn., vol. 59, no. 4, pp. 458–466, Apr. 2007, Accessed: Apr. 09, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3320