ANDERSON, J. A maximal Abelian subalgebra of the Calkin algebra with the extension property. MATHEMATICA SCANDINAVICA, [S. l.], v. 42, p. 101–110, 1978. DOI: 10.7146/math.scand.a-11739. Disponível em: https://www.mscand.dk/article/view/11739. Acesso em: 28 apr. 2024.