@article{SM_1973_19_3_a3,
     author = {L. A. Bunimovich and Ya. G. Sinai},
     title = {On~a~fundamental theorem in the theory of dispersing billiards},
     journal = {Sbornik. Mathematics},
     pages = {407--423},
     publisher = {mathdoc},
     volume = {19},
     number = {3},
     year = {1973},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1973_19_3_a3/}
}