Periodic Solutions of Strongly Nonlinear Oscillators Using He’s Frequency Formulation. European Journal of Pure and Applied Mathematics, Maryland, USA, v. 17, n. 3, p. 2155–2172, 2024. DOI: 10.29020/nybg.ejpam.v17i3.5339. Disponível em: https://www.ejpam.com/index.php/ejpam/article/view/5339. Acesso em: 2 dec. 2024.