ZHANG, Shuang. Toeplitz algebras and infinite simple $C^*$-algebras associated with reduced group $C^*$-algebras. Mathematica Scandinavica, Berkeley, CA, United States, v. 81, p. 86–100, 1997. DOI: 10.7146/math.scand.a-12867. Disponível em: https://journals.msp.org/mscand/article/view/1037. Acesso em: 25 jul. 2026.