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@article{DAN_1976_227_3_a5, author = {N. H. Ibragimov and R. L. Anderson}, title = {Groups of {Lie--B\"acklund} contact transformations}, journal = {Doklady Akademii Nauk}, pages = {539--542}, publisher = {mathdoc}, volume = {227}, number = {3}, year = {1976}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1976_227_3_a5/} }
N. H. Ibragimov; R. L. Anderson. Groups of Lie--B\"acklund contact transformations. Doklady Akademii Nauk, Tome 227 (1976) no. 3, pp. 539-542. http://geodesic.mathdoc.fr/item/DAN_1976_227_3_a5/