HANSEN, A. B. On a certain class of polytopes associated with independence systems. Mathematica Scandinavica, Berkeley, CA, United States, v. 41, p. 225–241, 1977. DOI: 10.7146/math.scand.a-11716. Disponível em: https://journals.msp.org/mscand/article/view/1930. Acesso em: 25 jul. 2026.