@article{SM_2020_211_8_a2,
     author = {S. S. Nikolaenko},
     title = {Topological classification of {Hamiltonian} systems on two-dimensional noncompact manifolds},
     journal = {Sbornik. Mathematics},
     pages = {1127--1158},
     year = {2020},
     volume = {211},
     number = {8},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2020_211_8_a2/}
}