Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1961_140_1_a15, author = {N. V. Stepanov}, title = {The geometry of two second-order ordinary differential equations}, journal = {Doklady Akademii Nauk}, pages = {62--65}, publisher = {mathdoc}, volume = {140}, number = {1}, year = {1961}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1961_140_1_a15/} }
N. V. Stepanov. The geometry of two second-order ordinary differential equations. Doklady Akademii Nauk, Tome 140 (1961) no. 1, pp. 62-65. http://geodesic.mathdoc.fr/item/DAN_1961_140_1_a15/