APA (7th ed.) Citation

Drachmann, A. B., Andersen, I., & Hill, G. F. (2009). Atheism in Pagan Antiquity. Project Gutenberg.

Chicago Style (17th ed.) Citation

Drachmann, A. B., Ingeborg Andersen, and George Francis Hill. Atheism in Pagan Antiquity. Project Gutenberg, 2009.

MLA (9th ed.) Citation

Drachmann, A. B., et al. Atheism in Pagan Antiquity. Project Gutenberg, 2009.

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