VESTERSTROM, J. On the Homomorphic Image of the Center of a $C^*$-Algebra. MATHEMATICA SCANDINAVICA, [S. l.], v. 29, p. 134–136, 1971. DOI: 10.7146/math.scand.a-11040. Disponível em: https://www.mscand.dk/article/view/11040. Acesso em: 5 may. 2024.