@article{DAN_1969_186_3_a7,
     author = {M. E. Ratner},
     title = {A central limit theorem for $Y$-flows on three-dimensional manifolds},
     journal = {Doklady Akademii Nauk},
     pages = {519--521},
     publisher = {mathdoc},
     volume = {186},
     number = {3},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_186_3_a7/}
}