ZHU, S.-D. Homotopy perturbation method for two point boundary value problems. Topological Methods in Nonlinear Analysis, [S. l.], v. 31, n. 2, p. 369–372, 2008. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2008.028. Acesso em: 26 apr. 2024.