@article{GDZPPN002346826,
title = {On the Integers Relatively Prime to n and a Number-Theoretic Function Considered by Jacobsthal.},
journal = {Mathematica Scandinavica},
volume = {11},
year = {1962},
pages = {163-170},
zbl = {0202.33002},
url = {http://dml.mathdoc.fr/item/GDZPPN002346826}
}
Erdös, P. On the Integers Relatively Prime to n and a Number-Theoretic Function Considered by Jacobsthal.. Mathematica Scandinavica, Tome 11 (1962) pp. 163-170. http://gdmltest.u-ga.fr/item/GDZPPN002346826/