TOPSOE, Flemming. Measure Spaces Connected by Correspondences. MATHEMATICA SCANDINAVICA, [S. l.], v. 30, p. 5–45, 1972. DOI: 10.7146/math.scand.a-11061. Disponível em: https://tidsskrift.dk/math/article/view/11061. Acesso em: 14 aug. 2026.