@article{10_4153_CJM_1977_095_1,
     author = {Berman, Gerald},
     title = {The {Dichromate} and {Orientations} of a {Graph}},
     journal = {Canadian journal of mathematics},
     pages = {947--956},
     year = {1977},
     volume = {29},
     number = {5},
     doi = {10.4153/CJM-1977-095-1},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1977-095-1/}
}