@article{AA_1989_1_2_a6,
     author = {V. F. Lazutkin},
     title = {Analytic integrals of a~semistandard mapping, and separatrix splitting},
     journal = {Algebra i analiz},
     pages = {116--131},
     year = {1989},
     volume = {1},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_1989_1_2_a6/}
}