@article{DAN_1974_216_4_a2,
     author = {M. G. Vitkov},
     title = {Cebysev approximations of the tangent},
     journal = {Doklady Akademii Nauk},
     pages = {721--723},
     publisher = {mathdoc},
     volume = {216},
     number = {4},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1974_216_4_a2/}
}