@article{SM_1972_16_2_a8,
     author = {B. I. Golubov},
     title = {Best approximations of functions in the $L_p$ metric by {Haar} and {Walsh} polynomials},
     journal = {Sbornik. Mathematics},
     pages = {265--285},
     publisher = {mathdoc},
     volume = {16},
     number = {2},
     year = {1972},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1972_16_2_a8/}
}