1. An identity between permanents and determinants;Gibson, P. M.;Amer. Math. Monthly,1969
2. On the relation between the determinant and the permanent;Marcus, Marvin;Illinois J. Math.,1961
3. On lower bounds for permanents of (0,1) matrices;Minc, Henryk;Proc. Amer. Math. Soc.,1969
4. G. Pólya, Aufgabe 424, Arch. Math. Phys. (3) 20 (1913), 271.