BURILKO, O. A.; SAMOILENKO, A. M. On the smoothness of the Green function for the problem of bounded invariant manifolds. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 4, p. 570–584, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4926. Acesso em: 5 dec. 2025.