RAEBURN, I.; SINCLAIR, A. M. The $C^*$-algebra generated by two projections. MATHEMATICA SCANDINAVICA, [S. l.], v. 65, p. 278–290, 1989. DOI: 10.7146/math.scand.a-12283. Disponível em: https://www.mscand.dk/article/view/12283. Acesso em: 30 apr. 2024.