@article{TM_1975_134_a18,
     author = {M. K. Potapov},
     title = {The structural characteristics of the classes of functions with a~given order of best approximation},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {260--277},
     publisher = {mathdoc},
     volume = {134},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1975_134_a18/}
}