NIELSEN, J. P. Cohomology of some non-selfadjoint operator algebras. MATHEMATICA SCANDINAVICA, [S. l.], v. 47, p. 150–156, 1980. DOI: 10.7146/math.scand.a-11881. Disponível em: https://www.mscand.dk/article/view/11881. Acesso em: 3 may. 2024.