DE, S. Vibrations of a Non-Homogeneous Annular Membrane. The Journal of the Indian Mathematical Society, [S. l.], v. 36, n. 3-4, p. 297–305, 1972. Disponível em: https://informaticsjournals.com/index.php/jims/article/view/16672. Acesso em: 7 may. 2024.