APA (7th ed.) Citation

Duffield, J. W. (2014). The Radio Boys Under the Sea or, The Hunt for Sunken Treasure. Project Gutenberg.

Chicago Style (17th ed.) Citation

Duffield, J. W. The Radio Boys Under the Sea or, The Hunt for Sunken Treasure. Project Gutenberg, 2014.

MLA (9th ed.) Citation

Duffield, J. W. The Radio Boys Under the Sea or, The Hunt for Sunken Treasure. Project Gutenberg, 2014.

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