Kopachevskii, N. D., and E. V. Semkina. “Complete Volterra Integrodifferential Equations of the Second Order Unsolved With Respect to the Higher Derivative”. Ukrains’kyi Matematychnyi Zhurnal 66, no. 11 (November 25, 2014): 1485–1497. Accessed April 26, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/2240.