APA (7th ed.) Citation

Butler, E. P., & Irvin, R. (2009). Philo Gubb, Correspondence-School Detective. Project Gutenberg.

Chicago Style (17th ed.) Citation

Butler, Ellis Parker, and Rea Irvin. Philo Gubb, Correspondence-School Detective. Project Gutenberg, 2009.

MLA (9th ed.) Citation

Butler, Ellis Parker, and Rea Irvin. Philo Gubb, Correspondence-School Detective. Project Gutenberg, 2009.

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