@article{RM_2017_72_3_a1,
     author = {S. V. Bolotin and V. V. Kozlov},
     title = {Topological approach to the generalized $n$-centre problem},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {451--478},
     publisher = {mathdoc},
     volume = {72},
     number = {3},
     year = {2017},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_2017_72_3_a1/}
}