@article{TMF_1987_70_3_a5,
     author = {V. B. Gostev and V. S. Mineev and A. R. Frenkin},
     title = {Oscillator with singular perturbation},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {384--393},
     year = {1987},
     volume = {70},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1987_70_3_a5/}
}