KAPLUN, Yu. I.; SAMOILENKO, V. G. On Extendability of Solutions of Differential Equations to a Singular Set. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 55, n. 3, p. 373–378, 2003. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3911. Acesso em: 6 dec. 2025.