@article{IVM_1977_12_a10,
     author = {A. B. Pevnyi},
     title = {Best approximation by piecewise parabolic functions},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {71--76},
     publisher = {mathdoc},
     number = {12},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1977_12_a10/}
}