Asymptotic methods in the theory of differential equations with a multivalued right-hand side. Neliniini Kolyvannya, [S. l.], v. 1, n. 1, p. 66–73, 1998. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/10. Acesso em: 22 jan. 2026.