Free Vibration Frequency of Thick FGM Spherical Shells Based on a Third-order Shear Deformation Theory. European Journal of Pure and Applied Mathematics, Maryland, USA, v. 13, n. 4, p. 766–778, 2020. DOI: 10.29020/nybg.ejpam.v13i4.3826. Disponível em: https://www.ejpam.com/index.php/ejpam/article/view/3826.. Acesso em: 4 may. 2024.