YUJI LIU; LIUMAN OU. The Existence of Periodic Solutions for Second Order Functional Differential Equations Caused by Impulses Effects. Jordan Journal of Mathematics and Statistics, [S. l.], v. 4, n. 3, p. 219–248, 2025. Disponível em: https://jjms.yu.edu.jo/index.php/jjms/article/view/1150. Acesso em: 10 sep. 2025.