@article{ Solr-acta15356, title = {On the divergence phenomena of the differentiated trigonometric projection operators}, series = {Acta scientiarum mathematicarum}, author = {Zhou Song Ping}, year = {1992}, url = {http://acta.bibl.u-szeged.hu/15356/1/math_056_fasc_003_004_323-328.pdf} }