@article{SM_1989_62_1_a5,
     author = {V. N. Temlyakov},
     title = {Estimates of the best bilinear approximations of functions of two},
     journal = {Sbornik. Mathematics},
     pages = {95--109},
     year = {1989},
     volume = {62},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1989_62_1_a5/}
}