BROWN, R. F. On Suitable Manifolds. MATHEMATICA SCANDINAVICA, [S. l.], v. 14, p. 174–178, 1964. DOI: 10.7146/math.scand.a-10715. Disponível em: https://www.mscand.dk/article/view/10715. Acesso em: 2 may. 2024.