STENBERG, W. On Weak Separation of Convex Sets and on $\alpha$-Ubiquitous Sets. MATHEMATICA SCANDINAVICA, [S. l.], v. 16, p. 55–74, 1965. DOI: 10.7146/math.scand.a-10748. Disponível em: https://www.mscand.dk/article/view/10748. Acesso em: 28 apr. 2024.