@article{SM_1969_9_2_a9,
     author = {A. L. Levin},
     title = {The distribution of poles of rational functions of best approximation and related questions},
     journal = {Sbornik. Mathematics},
     pages = {267--274},
     year = {1969},
     volume = {9},
     number = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1969_9_2_a9/}
}