HANSEN, Lundsgaard Vagn. 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://tidsskrift.dk/math/article/view/11031. Acesso em: 14 aug. 2026.