1. A proof of the irrationality of π;Breusch;Amer. Math. Monthly,1954
2. Similarities in irrationality proofs for π, ln2, ζ(2), and ζ(3);Huylebrouck;Amer. Math. Monthly,2001
3. A simple proof of the irrationality of π4;Hančl;Amer. Math. Monthly,1986
4. A simple proof of the irrationality of π;Nesterenko;Russ. J. Math. Phys.,2006
5. A simple proof that π is irrational;Niven;Bull. Amer. Math. Soc.,1947