@article{MZ_1939__45_168837,
     author = {A., Dinghas},
     title = {Zur {Invarianz} der {Shimizu-Ahlforsschen} {Charakteristik}},
     journal = {Mathematische Zeitschrift},
     pages = {25--28},
     publisher = {mathdoc},
     volume = {45},
     year = {1939},
     zbl = {0020.13905},
     url = {http://geodesic.mathdoc.fr/item/MZ_1939__45_168837/}
}