GAIKO, Valery A. Limit Cycles of Li´enard-Type Dynamical Systems. CUBO, A Mathematical Journal, [S. l.], v. 10, n. 3, p. 115–132, 2008. Disponível em: https://cubo.ufro.cl/index.php/cubo/article/view/1504. Acesso em: 8 jul. 2025.