@article{1077467066,
author = {Cohen, Eckford},
title = {Some totient functions},
journal = {Duke Math. J.},
volume = {23},
number = {1},
year = {1956},
pages = { 515-522},
language = {en},
url = {http://dml.mathdoc.fr/item/1077467066}
}
Cohen, Eckford. Some totient functions. Duke Math. J., Tome 23 (1956) no. 1, pp. 515-522. http://gdmltest.u-ga.fr/item/1077467066/