OLSEN, Catherine L.; PEDERSEN, Gert K. Corona $C^*$-algebras and their applications to lifting problems. Mathematica Scandinavica, Berkeley, CA, United States, v. 64, p. 63–86, 1989. DOI: 10.7146/math.scand.a-12248. Disponível em: https://journals.msp.org/mscand/article/view/1401. Acesso em: 25 jul. 2026.