@article{DE_2003_39_5_a1,
     author = {A. Yu. Kolesov and A. N. Kulikov and N. Kh. Rozov},
     title = {Invariant {Tori} of a {Class} of {Point} {Mappings:} {The} {Annulus} {Principle}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {584--601},
     publisher = {mathdoc},
     volume = {39},
     number = {5},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2003_39_5_a1/}
}