@article{DAN_1960_131_4_a9,
     author = {Ya. G. Sinai},
     title = {Geodesic flows on manifolds of negative constant curvature},
     journal = {Doklady Akademii Nauk},
     pages = {752--755},
     year = {1960},
     volume = {131},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1960_131_4_a9/}
}