APA (7th ed.) Citation

Le Queux, W. (2010). The Secrets of Potsdam. Project Gutenberg.

Chicago Style (17th ed.) Citation

Le Queux, William. The Secrets of Potsdam. Project Gutenberg, 2010.

MLA (9th ed.) Citation

Le Queux, William. The Secrets of Potsdam. Project Gutenberg, 2010.

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