@article{Tverberg_1963, title={On the Permanent of a Bistochastik Matrix.}, volume={12}, url={https://www.mscand.dk/article/view/10669}, DOI={10.7146/math.scand.a-10669}, journal={MATHEMATICA SCANDINAVICA}, author={Tverberg, Helge}, year={1963}, month={Dec.}, pages={25–35} }