@article{DE_1981_17_4_a1,
     author = {V. Y. Belozerov and G. V. Mozhaev},
     title = {Minimal possible number of controls in a linear time-invariant control system},
     journal = {Differencialʹnye uravneni\^a},
     pages = {589--597},
     publisher = {mathdoc},
     volume = {17},
     number = {4},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1981_17_4_a1/}
}