APA (7th ed.) Citation

Lardner, R., & Preston, M. W. (2011). Gullible's Travels, Etc. Project Gutenberg.

Chicago Style (17th ed.) Citation

Lardner, Ring, and May Wilson Preston. Gullible's Travels, Etc. Project Gutenberg, 2011.

MLA (9th ed.) Citation

Lardner, Ring, and May Wilson Preston. Gullible's Travels, Etc. Project Gutenberg, 2011.

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