@article{DE_1998_34_11_a4,
     author = {V. I. Elkin and D. G. Ivashko},
     title = {On a connection between the concepts of a $C$-system and an $L_1$-system in the theory of affine control systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1471--1477},
     publisher = {mathdoc},
     volume = {34},
     number = {11},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1998_34_11_a4/}
}