@article{RM_1986_41_5_a2,
     author = {N. V. Nikolenko},
     title = {The~method of {Poincar\'e} normal forms in problems of integrability of equations of evolution type},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {63--114},
     publisher = {mathdoc},
     volume = {41},
     number = {5},
     year = {1986},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1986_41_5_a2/}
}