Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{MAN_1927__96_159166, author = {H. Hopf}, title = {Vektorfelder in {n-dimensionalen-Mannigfaltigkeiten}}, journal = {Mathematische Annalen}, pages = {225--250}, publisher = {mathdoc}, volume = {96}, year = {1927}, zbl = {52.0571.01}, url = {http://geodesic.mathdoc.fr/item/MAN_1927__96_159166/} }
H. Hopf. Vektorfelder in n-dimensionalen-Mannigfaltigkeiten. Mathematische Annalen, Tome 96 (1927), pp. 225-250. http://geodesic.mathdoc.fr/item/MAN_1927__96_159166/