1. N. K. Nikolski, Operators, Functions and Systems: an Easy Reading. Vol. 1. Hardy, Hankel and Toeplitz, in Math. Surveys Monogr. (Amer. Math. Soc., Providence, RI, 2002), Vol. 92.
2. S. N. Mergelyan, “On the completeness of systems of analytic functions,” Uspekhi Mat. Nauk 8(4), 3–63 (1953). [Transl., Ser. 2, Am. Math. Soc. 19, 109–166 (1962)].
3. A. I. Markushevich, Theory of Analytic Functions: Further Construction of the Theory (Nauka, Moscow, 1968), Vol. 2 [in Russian].
4. N. I. Akhiezer, The Classical Moment Problem and Some Related Questions in Analysis (Fizmatgiz, Moscow, 1961; Hafner Publishing Co., New York, 1965).
5. N. I. Akhiezer, Lectures in Approximation Theory (Nauka, Moscow, 1965) [in Russian].