STROM, Arne. Note on Cofibrations. Mathematica Scandinavica, Berkeley, CA, United States, v. 19, p. 11–14, 1966. DOI: 10.7146/math.scand.a-10791. Disponível em: https://journals.msp.org/mscand/article/view/2550. Acesso em: 25 jul. 2026.