@article{ZNSL_1979_89_a6,
     author = {S. A. Vakulenko},
     title = {The influence of perturbation upons solitons of some nonlinear equations},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {91--96},
     publisher = {mathdoc},
     volume = {89},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1979_89_a6/}
}