APA (7th ed.) Citation

Le Queux, W. (2003). The Czar's Spy: The Mystery of a Silent Love. Project Gutenberg.

Chicago Style (17th ed.) Citation

Le Queux, William. The Czar's Spy: The Mystery of a Silent Love. Project Gutenberg, 2003.

MLA (9th ed.) Citation

Le Queux, William. The Czar's Spy: The Mystery of a Silent Love. Project Gutenberg, 2003.

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