@article{SM_1975_25_2_a0,
     author = {A. P. Bulanov},
     title = {Asymptotic behavior of the least deviations of the function $\operatorname{sgn}x$ from rational functions},
     journal = {Sbornik. Mathematics},
     pages = {159--176},
     publisher = {mathdoc},
     volume = {25},
     number = {2},
     year = {1975},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1975_25_2_a0/}
}