@article{DE_1988_24_2_a25,
     author = {G. G. Islamov},
     title = {Two-sided estimates for $s$-numbers of integral operators that increase smoothness},
     journal = {Differencialʹnye uravneni\^a},
     pages = {353--356},
     publisher = {mathdoc},
     volume = {24},
     number = {2},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1988_24_2_a25/}
}