Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1972_8_4_a19, author = {E. S. Kostenko}, title = {Group properties of ordinary second order linear differential equations}, journal = {Differencialʹnye uravneni\^a}, pages = {727--730}, publisher = {mathdoc}, volume = {8}, number = {4}, year = {1972}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1972_8_4_a19/} }
E. S. Kostenko. Group properties of ordinary second order linear differential equations. Differencialʹnye uravneniâ, Tome 8 (1972) no. 4, pp. 727-730. http://geodesic.mathdoc.fr/item/DE_1972_8_4_a19/