@article{ZNSL_2018_467_a18,
     author = {N. A. Shirokov},
     title = {A note about approximation by trigonometric polynomials},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {238--243},
     publisher = {mathdoc},
     volume = {467},
     year = {2018},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2018_467_a18/}
}