@article{DAN_1971_198_4_a9,
     author = {M. F. Timan},
     title = {The best approximation of periodic functions by trigonometric polynomials, and transforms of convolution type},
     journal = {Doklady Akademii Nauk},
     pages = {776--778},
     publisher = {mathdoc},
     volume = {198},
     number = {4},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_198_4_a9/}
}