@article{MZ_1944__50_169054,
     author = {Karl Strubecker},
     title = {Differentialgeometrie des isotropen {Raumes.} {IV.} {Theorie} der fl\"achentreuen {Abbildungen} der {Ebene.}},
     journal = {Mathematische Zeitschrift},
     pages = {1--92},
     publisher = {mathdoc},
     volume = {50},
     year = {1944},
     zbl = {0063.07216},
     url = {http://geodesic.mathdoc.fr/item/MZ_1944__50_169054/}
}