@article{MAN_1960__140_160770,
     author = {I. SINGER},
     title = {On best {Approximation} of {Continuous} {Functions.}},
     journal = {Mathematische Annalen},
     pages = {165--168},
     year = {1960},
     volume = {140},
     zbl = {0092.11601},
     url = {http://geodesic.mathdoc.fr/item/MAN_1960__140_160770/}
}