@article{RM_1974_29_3_a2,
     author = {N. P. Korneichuk},
     title = {On extremal problems in the theory of best approximation},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {7--43},
     publisher = {mathdoc},
     volume = {29},
     number = {3},
     year = {1974},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1974_29_3_a2/}
}