@article{DAN_1960_132_2_a0,
     author = {K. I. Babenko},
     title = {Approximation of periodic functions of many variables by trigonometric polynomials},
     journal = {Doklady Akademii Nauk},
     pages = {247--250},
     publisher = {mathdoc},
     volume = {132},
     number = {2},
     year = {1960},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1960_132_2_a0/}
}