ARASON, J.; MAGNUS, R. An algebraic multiplicity theory for analytic operator-valued functions. MATHEMATICA SCANDINAVICA, [S. l.], v. 82, n. 2, p. 265–286, 1998. DOI: 10.7146/math.scand.a-13837. Disponível em: https://www.mscand.dk/article/view/13837. Acesso em: 29 apr. 2024.