@article{SM_2019_210_3_a1,
     author = {V. V. Vedyushkina},
     title = {The {Fomenko--Zieschang} invariants of nonconvex topological billiards},
     journal = {Sbornik. Mathematics},
     pages = {310--363},
     publisher = {mathdoc},
     volume = {210},
     number = {3},
     year = {2019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2019_210_3_a1/}
}