@article{MOMA_1979__87_177904,
     author = {Wolfgang Schwarz},
     title = {Periodic, {Multiplicative} {Number-Theoretical} {Functions.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {65--68},
     publisher = {mathdoc},
     volume = {87},
     year = {1979},
     zbl = {0369.10033},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1979__87_177904/}
}