@article{GDZPPN002288303, title = {On best Approximation of Continuous Functions.}, journal = {Mathematische Annalen}, volume = {141}, year = {1960}, pages = {165-168}, zbl = {0092.11601}, url = {http://dml.mathdoc.fr/item/GDZPPN002288303} }
SINGER, I. On best Approximation of Continuous Functions.. Mathematische Annalen, Tome 141 (1960) pp. 165-168. http://gdmltest.u-ga.fr/item/GDZPPN002288303/