@article{ Solr-acta14147, title = {Smoothness conditions for Fourier series with monotone coefficients}, series = {Acta scientiarum mathematicarum}, author = {Askey Richard}, year = {1967}, url = {http://acta.bibl.u-szeged.hu/14147/1/math_028_fasc_001_002_169-171.pdf} }