@article{DAN_1970_191_6_a13,
     author = {A. G. Butkovskiy},
     title = {Finite control and controllability in distributed systems},
     journal = {Doklady Akademii Nauk},
     pages = {1247--1248},
     publisher = {mathdoc},
     volume = {191},
     number = {6},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_191_6_a13/}
}