@article{CMFD_2007_25_a9,
     author = {P. Oswald},
     title = {On $N${-Termed} {Approximations} in $H^s${-Norms} with {Respect} to the {Haar} {System}},
     journal = {Contemporary Mathematics. Fundamental Directions},
     pages = {106--125},
     publisher = {mathdoc},
     volume = {25},
     year = {2007},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/CMFD_2007_25_a9/}
}