@article{VMUMM_2020_1_a9,
     author = {V. V. Vedyushkina},
     title = {The {Liouville} foliation of the billiard book modelling the {Goryachev--Chaplygin} case},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {64--68},
     publisher = {mathdoc},
     number = {1},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2020_1_a9/}
}