@article{NGWGMP_1925__1925_59182,
     author = {H. Hopf},
     title = {Die {Curvatura} integra {Clifford-} {Kleinscher} {Raumformen}},
     journal = {Nachrichten von der Gesellschaft der Wissenschaften zu G\"ottingen, Mathematisch-Physikalische Klasse},
     pages = {131--141},
     publisher = {mathdoc},
     volume = {1925},
     year = {1925},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/NGWGMP_1925__1925_59182/}
}