Bounds for permanents of non-negative matrices

[1]  H. Minc.  A lower bound for permanents of (0,1)-matrices , 1967 .

[2]  H. Ryser,et al.  Matrix factorizations of determinants and permanents , 1966 .

[3]  M. Marcus,et al.  On a conjecture of B. L. van der Waerden , 1967, Mathematical Proceedings of the Cambridge Philosophical Society.