KARANDZHULOV, L. I. Boundary-value problems for parametric ordinary differential equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 4, p. 372–377, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5733. Acesso em: 15 dec. 2025.