@article{1077493375, author = {Gilbert, Paul W.}, title = {$n$ -to-one mappings of linear graphs}, journal = {Duke Math. J.}, volume = {9}, number = {1}, year = {1942}, pages = { 475-486}, language = {en}, url = {http://dml.mathdoc.fr/item/1077493375} }
Gilbert, Paul W. $n$ -to-one mappings of linear graphs. Duke Math. J., Tome 9 (1942) no. 1, pp. 475-486. http://gdmltest.u-ga.fr/item/1077493375/