@article{MOMA_1949__53_176805,
     author = {Walter Wunderlich},
     title = {Ein {Spiegelproblem.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {63--72},
     publisher = {mathdoc},
     volume = {53},
     year = {1949},
     zbl = {0035.09801},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1949__53_176805/}
}