@article{TMF_1980_42_3_a6,
     author = {E. M. Maslov},
     title = {Perturbation theory for solitons in~the second approximation},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {362--373},
     year = {1980},
     volume = {42},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1980_42_3_a6/}
}