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@article{DAN_1969_187_1_a12, author = {I. D. Cherkasov}, title = {Equivalence groups of second order linear differential equations}, journal = {Doklady Akademii Nauk}, pages = {50--52}, publisher = {mathdoc}, volume = {187}, number = {1}, year = {1969}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1969_187_1_a12/} }
I. D. Cherkasov. Equivalence groups of second order linear differential equations. Doklady Akademii Nauk, Tome 187 (1969) no. 1, pp. 50-52. http://geodesic.mathdoc.fr/item/DAN_1969_187_1_a12/