@article{AM2_1978__17_136748,
     author = {Charles R. Johnson},
     title = {An inclusion region for the field of values of a doubly stochastic matrix based on its graph.},
     journal = {Aequationes mathematicae},
     pages = {305--310},
     publisher = {mathdoc},
     volume = {17},
     year = {1978},
     zbl = {0384.15006},
     url = {http://geodesic.mathdoc.fr/item/AM2_1978__17_136748/}
}