@article{ZNSL_1997_243_a8,
     author = {I. N. Kostin},
     title = {Relatively unstable invariant sets of nonlinear operators},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {131--137},
     year = {1997},
     volume = {243},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1997_243_a8/}
}