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@article{MZM_1971_9_5_a0, author = {V. I. Berdyshev}, title = {Best approximations in $L_[0,infty)$ of the differentiation operator}, journal = {Matemati\v{c}eskie zametki}, pages = {477--481}, publisher = {mathdoc}, volume = {9}, number = {5}, year = {1971}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1971_9_5_a0/} }
V. I. Berdyshev. Best approximations in $L_[0,infty)$ of the differentiation operator. Matematičeskie zametki, Tome 9 (1971) no. 5, pp. 477-481. http://geodesic.mathdoc.fr/item/MZM_1971_9_5_a0/