@article{CMH_1962__37_139260,
     author = {George W. Whitehead},
     title = {Note on {Cross-sections} in {STIEFEL} {Manifolds.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {239--240},
     publisher = {mathdoc},
     volume = {37},
     year = {1962},
     zbl = {0118.18702},
     url = {http://geodesic.mathdoc.fr/item/CMH_1962__37_139260/}
}