DUPONT, Johan L. On Homotopy Invariance of the Tangent Bundle I. MATHEMATICA SCANDINAVICA, [S. l.], v. 26, p. 5–13, 1970. DOI: 10.7146/math.scand.a-10961. Disponível em: https://tidsskrift.dk/math/article/view/10961. Acesso em: 14 aug. 2026.