FOSGERAU, Mogens. Selection from Upper Semi-Continuous Compact-Valued Mappings. Mathematica Scandinavica, Berkeley, CA, United States, v. 76, p. 247–256, 1995. DOI: 10.7146/math.scand.a-12540. Disponível em: https://journals.msp.org/mscand/article/view/1082. Acesso em: 25 jul. 2026.