@article{DE_1999_35_5_a6,
     author = {N. N. Butenina},
     title = {Immunity zones of controlled dynamical systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {630--637},
     publisher = {mathdoc},
     volume = {35},
     number = {5},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1999_35_5_a6/}
}