@article{CMH_1973__48_139558,
     author = {H. Joris},
     title = {...-S\"atze f\"ur gewisse multiplikative arithmetische {Funktionen}},
     journal = {Commentarii mathematici Helvetici},
     pages = {409--435},
     year = {1973},
     volume = {48},
     zbl = {0282.12009},
     url = {http://geodesic.mathdoc.fr/item/CMH_1973__48_139558/}
}