@article{SM_2008_199_5_a0,
     author = {M. G. Grigoryan and A. A. Sargsyan},
     title = {Non-linear approximation of continuous functions
},
     journal = {Sbornik. Mathematics},
     pages = {629--653},
     publisher = {mathdoc},
     volume = {199},
     number = {5},
     year = {2008},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2008_199_5_a0/}
}