PETRYSHYN, Ya. R. Averaging of a multipoint problem with parameters for an impulsive oscillation system. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 52, n. 3, p. 419–423, 2000. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4433. Acesso em: 27 apr. 2025.