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@article{MZM_1989_45_2_a4, author = {A. V. Kolushov}, title = {Differential properties of the operator of best approximation by rational fractions}, journal = {Matemati\v{c}eskie zametki}, pages = {40--50}, publisher = {mathdoc}, volume = {45}, number = {2}, year = {1989}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1989_45_2_a4/} }
A. V. Kolushov. Differential properties of the operator of best approximation by rational fractions. Matematičeskie zametki, Tome 45 (1989) no. 2, pp. 40-50. http://geodesic.mathdoc.fr/item/MZM_1989_45_2_a4/