Poincaré Bifurcation from an Elliptic Hamiltonian of Degree Four with Two-Saddle Cycle. Journal of Nonlinear Modeling and Analysis, [S. l.], v. 4, n. 4, p. 722–735, 2024. DOI: 10.12150/jnma.2022.722. Disponível em: https://global-sci.com/index.php/jnma/article/view/13667. Acesso em: 6 dec. 2025.