@article{MZ_1928__28_168015,
     author = {W., Blaschke},
     title = {Topologische {Fragen} der {Differentialgeometrie.} {II.}},
     journal = {Mathematische Zeitschrift},
     pages = {158--160},
     publisher = {mathdoc},
     volume = {28},
     year = {1928},
     zbl = {54.0744.04},
     url = {http://geodesic.mathdoc.fr/item/MZ_1928__28_168015/}
}