APA (7th ed.) Citation

School Mathematics Study Group & Schaaf, W. L. (1967). Nature and history of Pi. Leland Stanford Junior University.

Chicago Style (17th ed.) Citation

School Mathematics Study Group and William L. Schaaf. Nature and History of Pi. Stanford, CA: Leland Stanford Junior University, 1967.

MLA (9th ed.) Citation

School Mathematics Study Group and William L. Schaaf. Nature and History of Pi. Leland Stanford Junior University, 1967.