FENG, H.; LI, Z. Existence and Uniqueness of Limit Cycles for a Class of Nonlinear Systems. Japan Journal of Research, [S. l.], v. 1, n. 2, 2023. Disponível em: https://journals.sciencexcel.com/index.php/jjr/article/view/11. Acesso em: 22 sep. 2024.