APA (7th ed.) Citation

Kelly-Bootle, S. (2006). The calculus formally known as pi. ACM queue : architecting tomorrow's computing..

Chicago Style (17th ed.) Citation

Kelly-Bootle, Stan. "The Calculus Formally Known as Pi." ACM Queue : Architecting Tomorrow's Computing. 2006.

MLA (9th ed.) Citation

Kelly-Bootle, Stan. "The Calculus Formally Known as Pi." ACM Queue : Architecting Tomorrow's Computing., 2006.