LAGODA, V. A.; PARASYUK, I. O.; SAMOILENKO, A. M. Lipschitzian invariant tori of indefinite monotone system. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 64, n. 3, p. 363–383, 2012. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2582. Acesso em: 11 apr. 2025.