NGUYEN, Van Dao; NGUYEN, Van Dinh; TRAN, Kim Chi. Van der Pol oscillator under parametric and forced excitations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 59, n. 2, p. 206–216, 2007. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3304. Acesso em: 6 dec. 2025.