APA (7th ed.) Citation

Gorky, M., Shirazi, J. K. M., & Chesterton, G. K. (1998). Creatures That Once Were Men. Project Gutenberg.

Chicago Style (17th ed.) Citation

Gorky, Maksim, J. K. M. Shirazi, and G. K. Chesterton. Creatures That Once Were Men. Project Gutenberg, 1998.

MLA (9th ed.) Citation

Gorky, Maksim, et al. Creatures That Once Were Men. Project Gutenberg, 1998.

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