@article{UMJ_2015_1_1_a7,
     author = {Yurii N. Subbotin},
     title = {One-sided widths of classes of smooth functions},
     journal = {Ural mathematical journal},
     pages = {83--86},
     publisher = {mathdoc},
     volume = {1},
     number = {1},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/UMJ_2015_1_1_a7/}
}