@article{DE_1971_7_3_a11,
     author = {V. M. Darevskii},
     title = {Representation of functions of two variables by means of differentiable trigonometric series for the solution of partial differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {486--500},
     publisher = {mathdoc},
     volume = {7},
     number = {3},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_3_a11/}
}