@article{1077489916, author = {Whitney, Hassler}, title = {On the maps of an $n$ -sphere into another $n$ -sphere}, journal = {Duke Math. J.}, volume = {3}, number = {1}, year = {1937}, pages = { 46-50}, language = {en}, url = {http://dml.mathdoc.fr/item/1077489916} }
Whitney, Hassler. On the maps of an $n$ -sphere into another $n$ -sphere. Duke Math. J., Tome 3 (1937) no. 1, pp. 46-50. http://gdmltest.u-ga.fr/item/1077489916/