@article{AM2_1984__27_137014,
     author = {Peter Volkmann and Norbert Steinmetz},
     title = {Funktionalgleichungen f\"ur konstante {Funktionen.}},
     journal = {Aequationes mathematicae},
     pages = {87--96},
     publisher = {mathdoc},
     volume = {27},
     year = {1984},
     zbl = {0544.39005},
     url = {http://geodesic.mathdoc.fr/item/AM2_1984__27_137014/}
}