STARUN, I. I.; SHKII, N. I. Integration of a singularly perturbed degenerate linear system. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 47, n. 11, p. 1542–1548, 1995. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5545. Acesso em: 7 apr. 2025.