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@article{IM2_1998_62_1_a5, author = {O. A. Timoshin}, title = {The best approximation to the operator of the second mixed derivative}, journal = {Izvestiya. Mathematics }, pages = {191--200}, publisher = {mathdoc}, volume = {62}, number = {1}, year = {1998}, language = {en}, url = {http://geodesic.mathdoc.fr/item/IM2_1998_62_1_a5/} }
O. A. Timoshin. The best approximation to the operator of the second mixed derivative. Izvestiya. Mathematics , Tome 62 (1998) no. 1, pp. 191-200. http://geodesic.mathdoc.fr/item/IM2_1998_62_1_a5/