@article{MS2_1976__38_166471,
     author = {Gunnar Dirdal},
     title = {Congruence properties for a class of arithmetical functions.},
     journal = {Mathematica Scandinavica},
     pages = {247--261},
     publisher = {mathdoc},
     volume = {38},
     year = {1976},
     zbl = {0337.10002},
     url = {http://geodesic.mathdoc.fr/item/MS2_1976__38_166471/}
}