KAUP, W. Contractive projections on Jordan $C^*$-algebras and generalizations. MATHEMATICA SCANDINAVICA, [S. l.], v. 54, p. 95–100, 1984. DOI: 10.7146/math.scand.a-12043. Disponível em: https://www.mscand.dk/article/view/12043. Acesso em: 24 nov. 2024.