Limit Cycles for a Class of Planar Differential Systems with a Degenerate Singular Point. Journal of Prime Research in Mathematics, [S. l.], v. 21, n. 1, p. 128–137, 2025. Disponível em: https://jprm.sms.edu.pk/index.php/jprm/article/view/277. Acesso em: 12 oct. 2025.