@article{MZM_1991_50_4_a17,
     author = {D. V. Treschev},
     title = {Preservation of invariant manifolds of {Hamiltonian} systems in the presence of a perturbation},
     journal = {Matemati\v{c}eskie zametki},
     pages = {123--131},
     publisher = {mathdoc},
     volume = {50},
     number = {4},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1991_50_4_a17/}
}