@article{MAN_1937__114_159913,
     author = {E. Tschech},
     title = {\"Uber {Kreise} und {Kugeln} im {Riemannschen} {Raum}},
     journal = {Mathematische Annalen},
     pages = {227--236},
     publisher = {mathdoc},
     volume = {114},
     year = {1937},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/MAN_1937__114_159913/}
}