A. V. Plotnikov and A. V. Tumbrukaki, “Integro-differential equations with multivalued solutions”, Ukr. Mat. Zhurn., vol. 52, no. 3, pp. 359–367, Mar. 2000, Accessed: Apr. 13, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/4426