@misc{RCM_2007_41_2_a8,
     title = {Unmixed bipartite graphs},
     journal = {Revista colombiana de matematicas},
     pages = {393--395},
     year = {2007},
     volume = {41},
     number = {2},
     url = {http://geodesic.mathdoc.fr/item/RCM_2007_41_2_a8/}
}