BLACKADAR, B. The Homotopy Lifting Theorem for Semiprojective $C^*$-Algebras. MATHEMATICA SCANDINAVICA, [S. l.], v. 118, n. 2, p. 291–302, 2016. DOI: 10.7146/math.scand.a-23691. Disponível em: https://www.mscand.dk/article/view/23691. Acesso em: 17 jan. 2022.