@article{DE_1976_12_5_a1,
     author = {L. E. Zabello and V. V. Mulyarchick},
     title = {The observability of nonstationary systems with lag},
     journal = {Differencialʹnye uravneni\^a},
     pages = {800--805},
     year = {1976},
     volume = {12},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_5_a1/}
}