1. [Al] K. Alladi,An Erdös-Kac theorem for integers without large prime factors, Acta Arith.49 (1987), 81–105.
2. [AO] N. C. Ankeny and H. Onishi,The general sieve, Acta Arith.10 (1964), 31–62.
3. [Be] J. J. A. Beenakker,The differential-difference equation αxf 1(x)+f(x−1)=0, Thesis, Eindhoven, 1966.
4. [BC] R. Bellimann and K. Cooke,Differential-Difference Equations, Academic Press, New York 1963.
5. [dB1] N. G. de Bruijn,On some Volterra integral equations of which all solutions are convergent, Nederl. Akad. Wetensch. Proc.53 (1950), 813–821.