RAHMAN, M. S. A perturbation technique to compute initial amplitude and phase for the Krylov-Bogoliubov-Mitropolskii method. Tamkang Journal of Mathematics, [S. l.], v. 43, n. 4, p. 563–575, 2012. DOI: 10.5556/j.tkjm.43.2012.853. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/853. Acesso em: 20 apr. 2024.