@article{TM_2016_295_a11,
     author = {A. P. Markeev},
     title = {On the stability of periodic trajectories of a~planar {Birkhoff} billiard},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {206--217},
     publisher = {mathdoc},
     volume = {295},
     year = {2016},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_2016_295_a11/}
}