@article{GDZPPN002195259,
title = {Multiplicative even functions (mod r). II Identities involving Ramanujan sums.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {302},
year = {1978},
pages = {44-50},
zbl = {0376.10007},
url = {http://dml.mathdoc.fr/item/GDZPPN002195259}
}
Sivaramakrishnan, R. Multiplicative even functions (mod r). II Identities involving Ramanujan sums.. Journal für die reine und angewandte Mathematik, Tome 302 (1978) pp. 44-50. http://gdmltest.u-ga.fr/item/GDZPPN002195259/