Tunç C, Erdur S. On the Existence of Periodic Solutions to Certain Non-linear Differential Equations of Third Order: On the Existence of Periodic Solutions. PPASA [Internet]. 2021 Apr. 29 [cited 2024 Nov. 9];54(2):207–218. Available from: https://ppaspk.org/index.php/PPAS-A/article/view/251