TVERBERG, H. On the Permanent of a Bistochastik Matrix. MATHEMATICA SCANDINAVICA, [S. l.], v. 12, p. 25–35, 1963. DOI: 10.7146/math.scand.a-10669. Disponível em: https://www.mscand.dk/article/view/10669. Acesso em: 25 apr. 2024.