@article{DE_1974_10_5_a2,
     author = {A. P. Ivanov and N. E. Kirin},
     title = {On methods of observing linear perturbable systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {788--791},
     publisher = {mathdoc},
     volume = {10},
     number = {5},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1974_10_5_a2/}
}