1. S. Aljan?i?,Sur le module de continuité des séries de Fourier particuliéres et sur le module de continuité des séries de Fourier transformées par des multiplicateurs de types divers, Bull. Acad. Serbe Sc. Arts. XL (1967), no. 6, 13?38.
2. S.A.Telyakovskii,Certain properties of sine series with monotone coefficients, Analisis Mathematica18 (1992), no. 4, 307?323. (Russian, English abstract)
3. S.A.Telyakovskii,On norms of trigonometric polynomials and approximation of differentiable functions by the linear averages of their Fourier series. I, Trudy Mat. Inst. Steklov62 (1961), 61?97; English transl. in Amer. Math. Soc. Transl. (2)28 (1963), 283?322.
4. G.M.Fikhtengol'ts,Differential and Integral Calculus, vol. 2, ?Nauka?, Moscow, 1970.