Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1969_189_3_a9, author = {L. S. Frank}, title = {Hyperbolic difference operators}, journal = {Doklady Akademii Nauk}, pages = {486--488}, publisher = {mathdoc}, volume = {189}, number = {3}, year = {1969}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1969_189_3_a9/} }
L. S. Frank. Hyperbolic difference operators. Doklady Akademii Nauk, Tome 189 (1969) no. 3, pp. 486-488. http://geodesic.mathdoc.fr/item/DAN_1969_189_3_a9/