@article{SM_2021_212_2_a3,
     author = {S. E. Pustovoitov},
     title = {Topological analysis of a~billiard bounded by confocal quadrics in a~potential field},
     journal = {Sbornik. Mathematics},
     pages = {211--233},
     publisher = {mathdoc},
     volume = {212},
     number = {2},
     year = {2021},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2021_212_2_a3/}
}