@article{SM_2021_212_9_a2,
     author = {A. A. Ershov and A. V. Ushakov and V. N. Ushakov},
     title = {Two game-theoretic problems of approach},
     journal = {Sbornik. Mathematics},
     pages = {1228--1260},
     year = {2021},
     volume = {212},
     number = {9},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2021_212_9_a2/}
}