ARCHBOLD, R. J. On commuting $C^*$-algebras of operators. Mathematica Scandinavica, Berkeley, CA, United States, v. 38, p. 106–114, 1976. DOI: 10.7146/math.scand.a-11621. Disponível em: https://journals.msp.org/mscand/article/view/2026. Acesso em: 25 jul. 2026.