@article{JMAG_2007_3_1_a5,
     author = {F. Peherstorfer and P. Yuditskii},
     title = {Uniform approximation of $sgn(x)$ by rational functions with prescribed poles},
     journal = {\v{Z}urnal matemati\v{c}eskoj fiziki, analiza, geometrii},
     pages = {95--108},
     year = {2007},
     volume = {3},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JMAG_2007_3_1_a5/}
}