@article{MZ_1929__30_168111,
     author = {K. Mayrhofer},
     title = {Topologische {Fragen} der {Differentialgeometrie.} {VII}},
     journal = {Mathematische Zeitschrift},
     pages = {144--148},
     publisher = {mathdoc},
     volume = {30},
     year = {1929},
     zbl = {55.1013.03},
     url = {http://geodesic.mathdoc.fr/item/MZ_1929__30_168111/}
}