ELGONDYEV, K. K.; SAMOILENKO, V. G. On periodic solutions of linear differential equations with pulsed influence. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 1, p. 141–148, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4992. Acesso em: 11 apr. 2025.