APA (7th ed.) Citation

Herbert, A. P. (2011). The Secret Battle. Project Gutenberg.

Chicago Style (17th ed.) Citation

Herbert, A. P. The Secret Battle. Project Gutenberg, 2011.

MLA (9th ed.) Citation

Herbert, A. P. The Secret Battle. Project Gutenberg, 2011.

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