OSUNA, Osvaldo; RODRÍGUEZ-CEBALLOS, Joel; VARGAS-DE-LEÓN, Cruz; VILLASEÑOR-AGUILAR, Gabriel. A note on the existence and construction of Dulac functions. Nonlinear Analysis: Modelling and Control, [S. l.], v. 22, n. 4, p. 431–440, 2017. DOI: 10.15388/NA.2017.4.1. Disponível em: https://www.journals.vu.lt/nonlinear-analysis/article/view/13376.. Acesso em: 2 may. 2024.