1. On the spectral synthesis of bounded functions;Beurling, Arne;Acta Math.,1948
2. Inequalities for monotonic series;Boas, R. P., Jr.;J. Math. Anal. Appl.,1960
3. The functions which operate on Fourier transforms;Helson, Henry;Acta Math.,1959
4. 4. A. A. Konyushkov, Nailuchshie priblizheniya trigonometricheskimi polinomami i koeffitsienty Fure, Mat. Sb. vol. 44 (86) (1958) pp. 53-84.