@article{1077379466, author = {Stevens, Harlan}, title = {Generalizations of the Euler $\varphi$ -function}, journal = {Duke Math. J.}, volume = {38}, number = {1}, year = {1971}, pages = { 181-186}, language = {en}, url = {http://dml.mathdoc.fr/item/1077379466} }
Stevens, Harlan. Generalizations of the Euler $\varphi$ -function. Duke Math. J., Tome 38 (1971) no. 1, pp. 181-186. http://gdmltest.u-ga.fr/item/1077379466/