@article{AM2_1978__17_136741,
     author = {Hans Schneider and D.J. Richman},
     title = {On the singular graph and the {Weyr} characteristic of an {M-matrix.}},
     journal = {Aequationes mathematicae},
     pages = {208--234},
     publisher = {mathdoc},
     volume = {17},
     year = {1978},
     zbl = {0379.15009},
     url = {http://geodesic.mathdoc.fr/item/AM2_1978__17_136741/}
}