@article{MZ_1978__164_172774,
     author = {Jost-Hinrich Eschenburg},
     title = {Trigonometrische {Charakterisierung} der {R\"aume} konstanter {Kr\"ummung.}},
     journal = {Mathematische Zeitschrift},
     pages = {143--152},
     year = {1978},
     volume = {164},
     zbl = {0389.53005},
     url = {http://geodesic.mathdoc.fr/item/MZ_1978__164_172774/}
}