HANSEN, A. B. On a certain class of polytopes associated with independence systems. MATHEMATICA SCANDINAVICA, [S. l.], v. 41, p. 225–241, 1977. DOI: 10.7146/math.scand.a-11716. Disponível em: https://www.mscand.dk/article/view/11716. Acesso em: 7 may. 2024.