N. D. Kopachevskii and E. V. Semkina, “Complete Volterra Integrodifferential Equations of the Second Order Unsolved with Respect to the Higher Derivative”, Ukr. Mat. Zhurn., vol. 66, no. 11, pp. 1485–1497, Nov. 2014, Accessed: Apr. 23, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2240