1. A. Zygmund, Trigonometric Series, Vol. 2 (Cambridge Univ. Press, Cambridge, 1960; Mir, Moscow, 1965).
2. F. Moricz, “On Double Cosine, Sine, and Walsh Series with Monotone Coefficients,” Proc. Amer. Math. Soc. 109(2), 417–435 (1990).
3. M. I. D’yachenko, “Norms of the Dirichlet Kernels and Some Other Trigonometric Polynomials in Spaces L p,” Matem. Sb. 184(3), 3–20 (1993).
4. O. S. Dragoshanskii, “Anizotropic Norms of the Dirichlet Kernels And Some Other Norms of Trigonometric Polynomials,” Matem. Zametki 67(5), 686–701 (2000).
5. G. G. Lorentz, “Fourier-Koeffizienten Und Funktionenklassen,” Math. Z. 51(2), 135–149 (1948).