@article{VMUMM_1999_2_a4,
     author = {Yu. A. Brailov and E. A. Kudryavtseva},
     title = {Stable topological nonconjugacy of {Hamiltonian} systems on two-dimensional surfaces},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {20--27},
     publisher = {mathdoc},
     number = {2},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1999_2_a4/}
}