APA (7th ed.) Citation

Woodrow, W., & Christy, H. C. (2008). The Silver Butterfly. Project Gutenberg.

Chicago Style (17th ed.) Citation

Woodrow, Wilson, and Howard Chandler Christy. The Silver Butterfly. Project Gutenberg, 2008.

MLA (9th ed.) Citation

Woodrow, Wilson, and Howard Chandler Christy. The Silver Butterfly. Project Gutenberg, 2008.

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