Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1957_117_2_a3, author = {S. E. Karapetyan}, title = {Second order {Lie} surface for ruled surfaces of congruence}, journal = {Doklady Akademii Nauk}, pages = {177--179}, publisher = {mathdoc}, volume = {117}, number = {2}, year = {1957}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1957_117_2_a3/} }
S. E. Karapetyan. Second order Lie surface for ruled surfaces of congruence. Doklady Akademii Nauk, Tome 117 (1957) no. 2, pp. 177-179. http://geodesic.mathdoc.fr/item/DAN_1957_117_2_a3/