[1] DICKSON D. G.: Asymptotic distribution of zeros of exponential polynomials. Publ. Math. Debrecen 11, 1964, 295-300. MR 0173770

[2] TIJDEMAN R.: On the distribution of the values of certain function. PhD Thes's Amsterdam 1969. MR 0259075

[3] TURÁN P.: Eine neue M thode in der Analysis und -deren Anwendungen. Akadem i Kiado Budapest 1953. MR 0060548

[4] van der POORTEN A. J.: On a Theorem of S. Dancs and P. Turán. Acta Math. Acad. Sci. Hungar 22, 1971, 359-364 MR 0294610

[5] van der POORTEN A. J.: Generalizing Turan's main theorems on lower bounds for sums of powers. Acta Math. Ac d. Sci. Hungar. 24, 1973, 93-96. MR 0313484 | Zbl 0264.30032