Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1990_48_1_a4, author = {A. M. Vinogradov and V. A. Yumaguzhin}, title = {Differential invariants of webs on 2-dimensional manifolds}, journal = {Matemati\v{c}eskie zametki}, pages = {26--37}, publisher = {mathdoc}, volume = {48}, number = {1}, year = {1990}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1990_48_1_a4/} }
A. M. Vinogradov; V. A. Yumaguzhin. Differential invariants of webs on 2-dimensional manifolds. Matematičeskie zametki, Tome 48 (1990) no. 1, pp. 26-37. http://geodesic.mathdoc.fr/item/MZM_1990_48_1_a4/