APA (7th ed.) Citation

Van Dyke, H. (2009). The Unknown Quantity: A Book of Romance and Some Half-Told Tales. Project Gutenberg.

Chicago Style (17th ed.) Citation

Van Dyke, Henry. The Unknown Quantity: A Book of Romance and Some Half-Told Tales. Project Gutenberg, 2009.

MLA (9th ed.) Citation

Van Dyke, Henry. The Unknown Quantity: A Book of Romance and Some Half-Told Tales. Project Gutenberg, 2009.

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