@article{RCM_1976__10_181654,
     author = {Osvaldo Marrero},
     title = {Eigenvalues of nonsingular matices and combinatorial applications},
     journal = {Revista colombiana de matematicas},
     pages = {121--124},
     year = {1976},
     volume = {10},
     zbl = {0354.05018},
     url = {http://geodesic.mathdoc.fr/item/RCM_1976__10_181654/}
}