@article{MZ_1933__36_168388,
     author = {K., Maruhn},
     title = {\"Uber den {Laplaceschen} {Ringk\"orper}},
     journal = {Mathematische Zeitschrift},
     pages = {122--142},
     publisher = {mathdoc},
     volume = {36},
     year = {1933},
     zbl = {0005.03103},
     url = {http://geodesic.mathdoc.fr/item/MZ_1933__36_168388/}
}