@article{00874302, title = {Some characterizations of totients.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {19}, year = {1996}, pages = {209-217}, doi = {10.1155/S0161171296000312}, zbl = {0846.11005}, language = {en}, url = {http://dml.mathdoc.fr/item/00874302} }
Haukkanen, Pentti. Some characterizations of totients.. International Journal of Mathematics and Mathematical Sciences, Tome 19 (1996) pp. 209-217. doi : 10.1155/S0161171296000312. http://gdmltest.u-ga.fr/item/00874302/