1. F. Beukers, A note on the irrationality of ζ(2) and ζ(3), to appear.
2. Notes of the Ziwet Lectures;E. Bombieri,1978
3. W. Kaplan, Advanced calculus, Addison-Wesley, Reading, Mass. (1951), 5 Ed.
4. L. M. Milne-Thompson, The calculus of finite differences, MacMillan and Co., London, (1933).
5. A. J. van der Poorten, A proof that Euler missed — Apéry's proof of the irrationality of ζ(3), Math. Intelligencer, to appear.