1. Differential — difference equations;Bellman,1963
2. On the algebraic approximation of functions IV;Coates;Proc. Kon. Akad. v. Wetensch., Ser. A, 70 = Indag. Math.,1967
3. On the distribution of values of a class of entire functions;Dancs;Publ. Math. Debrecen,1964
4. Asymptotic distribution of zeros of exponential sums;Dickson;Publ. Math. Debrecen,1964
5. Zeros of exponential sums;Dickson;Proc. Amer. Math. Soc.,1965