KARADZHOV, Yu. A. Singularly perturbed linear boundary-value problems with pulse effects and the regular reduced problem. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 47, n. 4, p. 463–467, 1995. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5443. Acesso em: 5 dec. 2025.