Global Phase Portraits of Symmetrical Cubic Hamiltonian Systems with a Nilpotent Singular Point. Journal of Nonlinear Modeling and Analysis, [S. l.], v. 1, n. 2, p. 193–205, 2024. DOI: 10.12150/jnma.2019.193. Disponível em: https://www.global-sci.com/index.php/jnma/article/view/13516. Acesso em: 5 dec. 2025.