1. A note on Riesz and Nörlund means;Dikshit, G. D.;Rend. Circ. Mat. Palermo (2),1969
2. G. H. Hardy, On the summability of Fourier series, Proc. London Math. Soc. (2) 12 (1913), 365-372
3. also in Collected papers of G. H Hardy, Vol. 3, Oxford Univ. Press, 1969, pp. 118-125.
4. Some new convergence criteria for Fourier series;Hardy, Godfrey Harold;Ann. Scuola Norm. Super. Pisa Cl. Sci. (2),1934
5. Absolute Nörlund summability;McFadden, Leonard;Duke Math. J.,1942