@article{CHEB_2019_20_4_a4,
     author = {M. G. Bashmakova and V. Kh. Salikhov},
     title = {On irrationality measure $\mathop{\mathrm{arctg}}\frac{1}{2}$},
     journal = {\v{C}eby\v{s}evskij sbornik},
     pages = {58--68},
     publisher = {mathdoc},
     volume = {20},
     number = {4},
     year = {2019},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/CHEB_2019_20_4_a4/}
}