APA (7th ed.) Citation

Persons, H. M. (2013). The Mystery of Arnold Hall. Project Gutenberg.

Chicago Style (17th ed.) Citation

Persons, Helen M. The Mystery of Arnold Hall. Project Gutenberg, 2013.

MLA (9th ed.) Citation

Persons, Helen M. The Mystery of Arnold Hall. Project Gutenberg, 2013.

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