@article{DE_2003_39_10_a0,
     author = {I. V. Gaishun},
     title = {Observable {Linear} {Nonstationary} {Systems} of {Total} {Differential} {Equations}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1299--1306},
     publisher = {mathdoc},
     volume = {39},
     number = {10},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2003_39_10_a0/}
}