@article{1183487067,
author = {Graustein, W. C.},
title = {An invariant of a general transformation of surfaces},
journal = {Bull. Amer. Math. Soc.},
volume = {32},
number = {5},
year = {1926},
pages = { 357-364},
language = {en},
url = {http://dml.mathdoc.fr/item/1183487067}
}
Graustein, W. C. An invariant of a general transformation of surfaces. Bull. Amer. Math. Soc., Tome 32 (1926) no. 5, pp. 357-364. http://gdmltest.u-ga.fr/item/1183487067/