ANDERSEN, T. B.; POULSEN, E. T. On Semi-Extremal Subsets of Convex Sets. Mathematica Scandinavica, Berkeley, CA, United States, v. 23, p. 167–168, 1968. DOI: 10.7146/math.scand.a-10906. Disponível em: https://journals.msp.org/mscand/article/view/2443. Acesso em: 25 jul. 2026.