ÖZIŞ, T.; YILDIRIM, A. Determination of limit cycles by iterated homotopy perturbation method for nonlinear oscillators with strong nonlinearity. Topological Methods in Nonlinear Analysis, [S. l.], v. 31, n. 2, p. 349–357, 2008. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2008.026. Acesso em: 17 jan. 2022.