BALANOV, Zalman; CHEN, Fulai; GUO, Jing; KRAWCEWICZ, Wiesław. Periodic solutions to reversible second order autonomous systems with commensurate delays. Topological Methods in Nonlinear Analysis, [S. l.], v. 59, n. 2A, p. 475–498, 2021. DOI: 10.12775/TMNA.2020.039. Disponível em: https://apcz.umk.pl/TMNA/article/view/34357. Acesso em: 28 jun. 2025.