@article{MAN_1960__141_160798,
     author = {H. G\"UNZLER},
     title = {Eine {Charakterisierung} harmonischer {Funktionen.}},
     journal = {Mathematische Annalen},
     pages = {68--86},
     publisher = {mathdoc},
     volume = {141},
     year = {1960},
     zbl = {0119.08901},
     url = {http://geodesic.mathdoc.fr/item/MAN_1960__141_160798/}
}