PTASHNIK, B. I.; SYLYUHA, L. P. Multipoint problem for typeless systems of differential equations with constant coefficients. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 9, p. 1236–1249, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5123. Acesso em: 5 dec. 2025.