@article{VMUMM_2020_4_a2,
     author = {V. V. Vedyushkina and V. A. Kibkalo},
     title = {Realization of numeri{\cyrs}al invariant of the {Siefert} bundle of integrable systems by billiards},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {22--28},
     year = {2020},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2020_4_a2/}
}