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@article{MZM_1982_31_1_a9, author = {L. G. Labsker}, title = {Korovkin sets in {Banach} space for sets of linear functionals}, journal = {Matemati\v{c}eskie zametki}, pages = {93--112}, publisher = {mathdoc}, volume = {31}, number = {1}, year = {1982}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1982_31_1_a9/} }
L. G. Labsker. Korovkin sets in Banach space for sets of linear functionals. Matematičeskie zametki, Tome 31 (1982) no. 1, pp. 93-112. http://geodesic.mathdoc.fr/item/MZM_1982_31_1_a9/