HAYASHI, M. . A Simple Criterion for the Non-Existence of Limit Cycles of a Lienard System. International Journal of Mathematical Research, [S. l.], v. 5, n. 2, p. 119–122, 2016. DOI: 10.18488/journal.24/2016.5.2/24.2.119.122. Disponível em: https://archive.conscientiabeam.com/index.php/24/article/view/2189. Acesso em: 18 may. 2024.