@article{DAN_1984_277_3_a4,
     author = {K. T. Mynbaev},
     title = {Bounds of the approximation numbers of imbeddings of anisotropic},
     journal = {Doklady Akademii Nauk},
     pages = {538--541},
     year = {1984},
     volume = {277},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1984_277_3_a4/}
}