HANSEN, L. V. Some Theorems on Direct Limits of Expanding Sequences of Manifolds. MATHEMATICA SCANDINAVICA, [S. l.], v. 29, p. 5–36, 1971. DOI: 10.7146/math.scand.a-11031. Disponível em: https://www.mscand.dk/article/view/11031. Acesso em: 4 may. 2024.