MORSE, M. On Elevating Manifold Differentiability. The Journal of the Indian Mathematical Society, [S. l.], v. 24, n. 3-4, p. 379–400, 1960. DOI: 10.18311/jims/1960/16921. Disponível em: https://informaticsjournals.com/index.php/jims/article/view/16921. Acesso em: 4 may. 2024.