@article{IVM_1980_4_a9,
     author = {A. A. Ligun},
     title = {Best approximation of differentiable functions by algebraic polynomials},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {53--60},
     publisher = {mathdoc},
     number = {4},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1980_4_a9/}
}