Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1960_132_1_a9, author = {L. V. Ovsyannikov}, title = {Determination of the group of a linear second-order differential equation}, journal = {Doklady Akademii Nauk}, pages = {44--47}, publisher = {mathdoc}, volume = {132}, number = {1}, year = {1960}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1960_132_1_a9/} }
L. V. Ovsyannikov. Determination of the group of a linear second-order differential equation. Doklady Akademii Nauk, Tome 132 (1960) no. 1, pp. 44-47. http://geodesic.mathdoc.fr/item/DAN_1960_132_1_a9/