1. Pi: A Source Book;Berggren,2004
2. Ramanujan's Notebooks Part III;Berndt,1991
3. On Ramanujan's quartic theory of elliptic functions;Berndt;J. Number Theory,2001
4. Ramanujan's singular moduli;Berndt;Ramanujan J.,1997
5. Pi and the AGM: A Study in Analytic Number Theory and Computational Complexity;Borwein,1987