STEFANSSON, Jón R. On a Problem of J. Dixmier Concerning Ideals in a von Neumann Algebra. Mathematica Scandinavica, Berkeley, CA, United States, v. 24, p. 111–112, 1969. DOI: 10.7146/math.scand.a-10924. Disponível em: https://journals.msp.org/mscand/article/view/2377. Acesso em: 25 jul. 2026.