Vityuk, A. N. “Solvability of a Three-Point Boundary-Value Problem for a Second-Order Differential Inclusion”. Ukrains’kyi Matematychnyi Zhurnal 55, no. 1 (January 25, 2003): 132–137. Accessed December 6, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/3895.