1. Chandra P.: On the absolute Riesz summability of a Fourier series and its application to the absolute convergence of Fourier series. J. Lond. Math. Soc. 4(2), 611–617 (1972)
2. Karamata, J.: Théorèmes sur la sommabilitié exponentielle et d’autres sommabilitiés s′y rattachant. Mathematica Cluj. 9, 164–178 (1935)
3. Kogbetliantz E.: Sur les series absolument sommables par le methode des moyennes arithmetique. Bull. des. Sc Math. 49(2), 234–256 (1925)
4. Lal S.: On K λ summability of conjugate series of Fourier series. Bull. Calcutta Math. Soc. 89, 97–104 (1997)
5. Lototsky, A.V.: On a linear transformation of sequences and series. Ivanov. Gos. Ped. Inst. Uc. Zap. Fiz-Mat. Nauki 4, 61–91 (1953, Russian)