@article{MOMA_1973__77_177655,
     author = {Karl Rabl},
     title = {Das {Problem} perspektiver {B\"unde.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {345--353},
     publisher = {mathdoc},
     volume = {77},
     year = {1973},
     zbl = {0273.50009},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1973__77_177655/}
}