@article{DE_1968_4_1_a11,
     author = {E. A. Volkov},
     title = {The unimprovability of the error estimate of the method of refinements with higher order differences in a certain class of solutions of {Poisson's} equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {136--139},
     publisher = {mathdoc},
     volume = {4},
     number = {1},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1968_4_1_a11/}
}