HOLM, P. Excision and Cofibrations. MATHEMATICA SCANDINAVICA, [S. l.], v. 19, p. 122–126, 1966. DOI: 10.7146/math.scand.a-10800. Disponível em: https://www.mscand.dk/article/view/10800. Acesso em: 28 apr. 2024.