LIN, Huaxin. The simplicity of the quotient algebra $M(A)/A$ of a simple $C^*$-algebra. Mathematica Scandinavica, Berkeley, CA, United States, v. 65, p. 119–128, 1989. DOI: 10.7146/math.scand.a-12270. Disponível em: https://journals.msp.org/mscand/article/view/1380. Acesso em: 25 jul. 2026.