@article{TM_1992_198_a11,
     author = {I. G. Tsar'kov},
     title = {Widths and {Jackson's} type inequality for abstract functions},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {219--231},
     publisher = {mathdoc},
     volume = {198},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1992_198_a11/}
}