@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/