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@article{TRSPY_1967_88_a5, author = {N. I. Chernykh}, title = {Jackson's inequality in $L_2$}, journal = {Informatics and Automation}, pages = {71--74}, publisher = {mathdoc}, volume = {88}, year = {1967}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/TRSPY_1967_88_a5/} }
N. I. Chernykh. Jackson's inequality in $L_2$. Informatics and Automation, Approximation of functions in the mean, Tome 88 (1967), pp. 71-74. http://geodesic.mathdoc.fr/item/TRSPY_1967_88_a5/