@article{DE_1990_26_12_a13,
     author = {A. P. Soldatov},
     title = {Functional operators with a shift},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2136--2145},
     year = {1990},
     volume = {26},
     number = {12},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1990_26_12_a13/}
}