@article{VMUMM_2021_5_a1,
     author = {S. E. Pustovoitov},
     title = {Topological analysis of an elliptic billiard in a fourth-order potential field},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {8--19},
     year = {2021},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2021_5_a1/}
}