ŚLOSARSKI, M. Metrizable space of multivalued maps. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 20, p. 77–93, 2021. Disponível em: https://studmath.up.krakow.pl/article/view/8523. Acesso em: 19 jan. 2022.