@article{1077489100, author = {Lefschetz, S.}, title = {On critical sets}, journal = {Duke Math. J.}, volume = {1}, number = {1}, year = {1935}, pages = { 392-412}, language = {en}, url = {http://dml.mathdoc.fr/item/1077489100} }
Lefschetz, S. On critical sets. Duke Math. J., Tome 1 (1935) no. 1, pp. 392-412. http://gdmltest.u-ga.fr/item/1077489100/