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@article{DAN_1982_264_5_a7, author = {A. V. Kolushov}, title = {On differentiability of the operator of best approximation by rational fractions}, journal = {Doklady Akademii Nauk}, pages = {1060--1062}, publisher = {mathdoc}, volume = {264}, number = {5}, year = {1982}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1982_264_5_a7/} }
A. V. Kolushov. On differentiability of the operator of best approximation by rational fractions. Doklady Akademii Nauk, Tome 264 (1982) no. 5, pp. 1060-1062. http://geodesic.mathdoc.fr/item/DAN_1982_264_5_a7/