@article{DE_1967_3_6_a13,
     author = {A. L. Teptin},
     title = {Conditions of validity of {\v {C}aplygin's} theorem for elliptic difference equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1009--1021},
     publisher = {mathdoc},
     volume = {3},
     number = {6},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1967_3_6_a13/}
}