Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1983_19_12_a9, author = {G. V. Zhidkov}, title = {Differential properties of functions on the sphere}, journal = {Differencialʹnye uravneni\^a}, pages = {2090--2101}, publisher = {mathdoc}, volume = {19}, number = {12}, year = {1983}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1983_19_12_a9/} }
G. V. Zhidkov. Differential properties of functions on the sphere. Differencialʹnye uravneniâ, Tome 19 (1983) no. 12, pp. 2090-2101. http://geodesic.mathdoc.fr/item/DE_1983_19_12_a9/