FEDERSON, M.; SCHWABIK, Š. Stability for retarded functional differential equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 60, n. 1, p. 107–126, 2008. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3142. Acesso em: 14 apr. 2025.