1. The distribution of zeros of certain entire functions;DePree;J. Math. Anal. Appl.,1965
2. Differential-Difference Equations;Bellman,1962
3. Integral functions;Cartwright;Cambridge Tracts in Math. and Math. Phys.,1962
4. Introduction to the Theory of Fourier Integrals;Titchmarsh,1948
5. Distribution of zeros of entire functions;Levin;Trans. Math. Mon.,1964