@article{DAN_1992_326_3_a6,
     author = {M. B. Sevryuk},
     title = {Invariant tori of reversible systems in the presence of additional even coordinates},
     journal = {Doklady Akademii Nauk},
     pages = {421--424},
     publisher = {mathdoc},
     volume = {326},
     number = {3},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1992_326_3_a6/}
}