ANDERSON, Joel. A maximal Abelian subalgebra of the Calkin algebra with the extension property. Mathematica Scandinavica, Berkeley, CA, United States, v. 42, p. 101–110, 1978. DOI: 10.7146/math.scand.a-11739. Disponível em: https://journals.msp.org/mscand/article/view/1910. Acesso em: 25 jul. 2026.