@article{TRSPY_1992_198_a13,
     author = {V. T. Shevaldin},
     title = {Lower estimations of widths some classes of periodic functions},
     journal = {Informatics and Automation},
     pages = {242--267},
     publisher = {mathdoc},
     volume = {198},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1992_198_a13/}
}