APA (7th ed.) Citation

Verne, J., & Kingston, W. H. G. (2007). The Secret of the Island. Project Gutenberg.

Chicago Style (17th ed.) Citation

Verne, Jules, and William Henry Giles Kingston. The Secret of the Island. Project Gutenberg, 2007.

MLA (9th ed.) Citation

Verne, Jules, and William Henry Giles Kingston. The Secret of the Island. Project Gutenberg, 2007.

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