GAETA, Giuseppe. Further reduction of Poincaré-Dulac normal forms in symmetric systems. CUBO, A Mathematical Journal, [S. l.], v. 9, n. 3, p. 1–11, 2007. Disponível em: https://cubo.ufro.cl/index.php/cubo/article/view/1583. Acesso em: 3 nov. 2025.