David E. Scheim. The number of edge 3-colorings of a planar cubic graph as a permanent. Discrete Mathematics, 8(4):377-382, 1974. [doi]
@article{Scheim74,
title = {The number of edge 3-colorings of a planar cubic graph as a permanent},
author = {David E. Scheim},
year = {1974},
doi = {10.1016/0012-365X(74)90157-5},
url = {http://dx.doi.org/10.1016/0012-365X(74)90157-5},
researchr = {https://researchr.org/publication/Scheim74},
cites = {0},
citedby = {0},
journal = {Discrete Mathematics},
volume = {8},
number = {4},
pages = {377-382},
}