@article{MAN_1930__103_159420,
     author = {G. Gr\"uss},
     title = {Beitr\"age zur {Differentialgeometrie} zweidimensionaler allgemein-metrischer {Fl\"achen}},
     journal = {Mathematische Annalen},
     pages = {162--184},
     publisher = {mathdoc},
     volume = {103},
     year = {1930},
     zbl = {56.0632.01},
     url = {http://geodesic.mathdoc.fr/item/MAN_1930__103_159420/}
}