@article{IVM_1973_1_a5,
     author = {V. V. Zhuk},
     title = {Certain sharp inequalities between best approximations},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {51--56},
     publisher = {mathdoc},
     number = {1},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1973_1_a5/}
}