@article{DE_1969_5_6_a8,
     author = {S. V. Churakova},
     title = {The relative controllability of linear systems with variable and distributed retardation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1068--1075},
     publisher = {mathdoc},
     volume = {5},
     number = {6},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1969_5_6_a8/}
}