1. D. Jackson, Fourier Series and Orthogonal Polynomials [Russian translation], IL, Moscow (1948).
2. G. Freud, ?Über die Konvergenz orthogonaler Polynomreihen,? Acta Math. Acad. Sci. Hung.,3, Nos. 1?2, 89?98 (1952).
3. Ya. L. Geronimus, Polynomials Orthogonal on a Circle and Interval [in Russian], Fizmatgiz, Moscow (1958).
4. N. N. Luzin, Theory of Functions of a Real Variable [in Russian], Uchpedgiz, Moscow (1948).
5. N. I. Akhiezer, Lectures on the Theory of Approximation [in Russian], Nauka, Moscow (1965).