COMFORT, W. W.; HAGER, Anthony W. The Projection Mapping and Other Continuous Functions on a Product Space. MATHEMATICA SCANDINAVICA, [S. l.], v. 28, p. 77–90, 1971. DOI: 10.7146/math.scand.a-11007. Disponível em: https://www.mscand.dk/article/view/11007. Acesso em: 5 dec. 2025.