Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{CMH_1956__30_139117, author = {H. Wittich}, title = {\"Uber eine {Klasse} {Riemannscher} {Fl\"achen.}}, journal = {Commentarii mathematici Helvetici}, pages = {116--123}, publisher = {mathdoc}, volume = {30}, year = {1956}, language = {de}, url = {http://geodesic.mathdoc.fr/item/CMH_1956__30_139117/} }
H. Wittich. Über eine Klasse Riemannscher Flächen.. Commentarii mathematici Helvetici, Tome 30 (1956), pp. 116-123. http://geodesic.mathdoc.fr/item/CMH_1956__30_139117/