Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1963_150_6_a7, author = {N. P. Korneichuk}, title = {The exact value of best approximations and widths of certain classes of functions}, journal = {Doklady Akademii Nauk}, pages = {1218--1220}, publisher = {mathdoc}, volume = {150}, number = {6}, year = {1963}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1963_150_6_a7/} }
N. P. Korneichuk. The exact value of best approximations and widths of certain classes of functions. Doklady Akademii Nauk, Tome 150 (1963) no. 6, pp. 1218-1220. http://geodesic.mathdoc.fr/item/DAN_1963_150_6_a7/