VASYLYSHYN, P. B.; PTASHNIK, B. I. A multipoint problem for partial integro-differential equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 9, p. 1155–1168, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4832. Acesso em: 6 dec. 2025.