@article{CMH_1935__8_138657,
     author = {E. Stiefel},
     title = {Richtungsfelder und {Fernparallelismus} in n-dimensionalen {Mannigfaltigkeiten.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {305--353},
     publisher = {mathdoc},
     volume = {8},
     year = {1935},
     zbl = {62.0662.02},
     url = {http://geodesic.mathdoc.fr/item/CMH_1935__8_138657/}
}