1. Concrete Mathematics;Graham,1989
2. A simple derivation of the Leibniz–Gregory series for π/4;Kazarinoff;Amer. Math. Monthly,1955
3. Zur Approximation von e durch (1+1/n)n;Rautenberg;Math. Semesterber.,1986
4. Problem E 3432;Tóth;Amer. Math. Monthly,1991
5. On a class of Leibniz series;Tóth;Rev. Anal. Numér. Théor. Approx.,1992