@article{00770114, title = {Some negative results concerning the process of Fej\'er type trigonometric convolution.}, journal = {Georgian Mathematical Journal}, volume = {2}, year = {1995}, pages = {313-322}, doi = {10.1007/BF02261704}, zbl = {0842.42004}, language = {en}, url = {http://dml.mathdoc.fr/item/00770114} }
Oniani, G. Some negative results concerning the process of Fejér type trigonometric convolution.. Georgian Mathematical Journal, Tome 2 (1995) pp. 313-322. doi : 10.1007/BF02261704. http://gdmltest.u-ga.fr/item/00770114/