@article{DAN_1996_346_5_a2,
     author = {M. B. Sevryuk},
     title = {Invariant tori of {Hamiltonian} systems that are nondegenerate in {R\"ussmann{\textquoteright}s} sense},
     journal = {Doklady Akademii Nauk},
     pages = {590--593},
     year = {1996},
     volume = {346},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1996_346_5_a2/}
}