1. N.I. Akhiezer, Lectures on Approximation Theory. Nauka, 1965.
2. Theory of Linear Operators in Hilbert Space;Akhiezer,1993
3. Sur une propriété de fonctions entières;Bernstein;C. R. Math. Acad. Sci. Paris,1923
4. Time series and harmonic analysis;Doob,1949
5. Stochastic Processes;Doob,1990