@article{MZM_1978_23_6_a4,
     author = {S. A. Agahanov and N. Sh. Zagirov},
     title = {Approximation of the function sign x in the uniform and integral metrics by means of rational functions},
     journal = {Matemati\v{c}eskie zametki},
     pages = {825--838},
     publisher = {mathdoc},
     volume = {23},
     number = {6},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1978_23_6_a4/}
}