@article{SEMR_2021_18_2_a70,
     author = {R. R. Akopyan},
     title = {Best approximation of differentiation operators on the {Sobolev} class of functions analytic in a strip},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {1286--1298},
     publisher = {mathdoc},
     volume = {18},
     number = {2},
     year = {2021},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2021_18_2_a70/}
}