VasylyshynP. B., and PtashnikB. I. “A Multipoint Problem for Partial Integro-Differential Equations”. Ukrains’kyi Matematychnyi Zhurnal 50, no. 9 (September 25, 1998): 1155–1168. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4832.