Rocsoreanu, Carmen, and Mihaela Sterpu. “Homoclinic and Heteroclinic Orbits for a Liénard System”. Journal of Informatics and Mathematical Sciences 10, no. 4 (December 31, 2018): 563–571. Accessed November 24, 2024. http://rgnpublications.com/journals/index.php/jims/article/view/1048.