@article{MZM_1996_59_1_a4,
     author = {R. F. Bikbaev},
     title = {Nondegeneracy of amplitude-frequency modulation for finite-gap solutions of integrable nonlinear equations},
     journal = {Matemati\v{c}eskie zametki},
     pages = {53--61},
     publisher = {mathdoc},
     volume = {59},
     number = {1},
     year = {1996},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1996_59_1_a4/}
}