APA (7th ed.) Citation

Butler, E. P. (1999). Pigs is Pigs. Project Gutenberg.

Chicago Style (17th ed.) Citation

Butler, Ellis Parker. Pigs Is Pigs. Project Gutenberg, 1999.

MLA (9th ed.) Citation

Butler, Ellis Parker. Pigs Is Pigs. Project Gutenberg, 1999.

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