Error estimates for the averaging method in impulsive boundary-value problems with parameters. Neliniini Kolyvannya, [S. l.], v. 5, n. 2, p. 193–207, 2002. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/213. Acesso em: 22 jan. 2026.