A graph theoretic upper bound on the permanent of a nonnegative integer matrix. I
If A is a fully indecomposable \(n\times n\) matrix with nonnegative integer entries which has row and column \(r_ i\) and \(c_ i\), respectively, then \(per A\leq 1+\min [\prod_{i}(r_ i-1),\quad \prod_{i}(c_ i-1)].\)
scientific article; zbMATH DE number 3877357