@article{IM2_1989_32_1_a2,
     author = {S. B. Kuksin},
     title = {Perturbation of quasiperiodic solutions of infinite-dimensional {Hamiltonian} systems},
     journal = {Izvestiya. Mathematics},
     pages = {39--62},
     year = {1989},
     volume = {32},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1989_32_1_a2/}
}