@article{DAN_1988_301_2_a2,
     author = {D. G. Vasil'ev and Yu. G. Safarov},
     title = {Branching {Hamiltonian} billiards},
     journal = {Doklady Akademii Nauk},
     pages = {271--275},
     publisher = {mathdoc},
     volume = {301},
     number = {2},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1988_301_2_a2/}
}