Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{MAN_1981__256_163499, author = {Klaus J\"anich}, title = {Universal {Families} of {C{\textdegree}{\textdegree}-Functions} on {D2.}}, journal = {Mathematische Annalen}, pages = {67--84}, publisher = {mathdoc}, volume = {256}, year = {1981}, zbl = {0442.58006}, url = {http://geodesic.mathdoc.fr/item/MAN_1981__256_163499/} }
Klaus Jänich. Universal Families of C°°-Functions on D2.. Mathematische Annalen, Tome 256 (1981), pp. 67-84. http://geodesic.mathdoc.fr/item/MAN_1981__256_163499/