@article{1077472821,
author = {Haviland, E. K.},
title = {An analogue of Euler's $\varphi$ -function},
journal = {Duke Math. J.},
volume = {11},
number = {1},
year = {1944},
pages = { 869-872},
language = {en},
url = {http://dml.mathdoc.fr/item/1077472821}
}
Haviland, E. K. An analogue of Euler’s $\varphi$ -function. Duke Math. J., Tome 11 (1944) no. 1, pp. 869-872. http://gdmltest.u-ga.fr/item/1077472821/