@article{DE_1973_9_5_a21,
     author = {V. P. Kirlitsa},
     title = {Invariance of a certain linear system with lag},
     journal = {Differencialʹnye uravneni\^a},
     pages = {955--957},
     publisher = {mathdoc},
     volume = {9},
     number = {5},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1973_9_5_a21/}
}