HOPENWASSER, Alan. Isometries on Irreducible Triangular Operator Algebras. MATHEMATICA SCANDINAVICA, [S. l.], v. 30, p. 136–140, 1972. DOI: 10.7146/math.scand.a-11069. Disponível em: https://tidsskrift.dk/math/article/view/11069. Acesso em: 14 aug. 2026.