Bi-Center Problem in a Class of $Z_2$-Equivariant Quintic Vector Fields. Journal of Nonlinear Modeling and Analysis, [S. l.], v. 2, n. 1, p. 57–78, 2024. DOI: 10.12150/jnma.2020.57. Disponível em: https://global-sci.com/index.php/jnma/article/view/13547. Acesso em: 6 dec. 2025.