@article{RM_1977_32_3_a5,
     author = {M. Voitkovski},
     title = {Symbolic dynamics in a~billiard problem},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {32},
     number = {3},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1977_32_3_a5/}
}