APA (7th ed.) Citation

Hemphill, S. (1990). The number Pi. Project Gutenberg.

Chicago Style (17th ed.) Citation

Hemphill, Scott. The Number Pi. Champaign, Ill: Project Gutenberg, 1990.

MLA (9th ed.) Citation

Hemphill, Scott. The Number Pi. Project Gutenberg, 1990.

Warning: These citations may not always be 100% accurate.