Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1994_55_5_a0, author = {V. K. Beloshapka}, title = {Geometric invariants of a $CR$-manifold}, journal = {Matemati\v{c}eskie zametki}, pages = {3--12}, publisher = {mathdoc}, volume = {55}, number = {5}, year = {1994}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1994_55_5_a0/} }
V. K. Beloshapka. Geometric invariants of a $CR$-manifold. Matematičeskie zametki, Tome 55 (1994) no. 5, pp. 3-12. http://geodesic.mathdoc.fr/item/MZM_1994_55_5_a0/