@article{MZM_1969_6_6_a5,
     author = {M. E. Ratner},
     title = {Markov splitting for {U-flows} in three-dimensional manifolds},
     journal = {Matemati\v{c}eskie zametki},
     pages = {693--704},
     year = {1969},
     volume = {6},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1969_6_6_a5/}
}