@article{DE_1986_22_4_a1,
     author = {I. U. Bronshtein},
     title = {Necessary conditions for the preservation of smooth invariant submanifolds},
     journal = {Differencialʹnye uravneni\^a},
     pages = {573--581},
     publisher = {mathdoc},
     volume = {22},
     number = {4},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1986_22_4_a1/}
}