@article{RM_1999_54_5_a10,
     author = {S. P. Novikov},
     title = {Levels of quasiperiodic functions on a~plane, and {Hamiltonian} systems},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {1031--1032},
     publisher = {mathdoc},
     volume = {54},
     number = {5},
     year = {1999},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1999_54_5_a10/}
}