APA (7th ed.) Citation

Oppenheim, E. P. (2003). The Double Traitor. Project Gutenberg.

Chicago Style (17th ed.) Citation

Oppenheim, E. Phillips. The Double Traitor. Project Gutenberg, 2003.

MLA (9th ed.) Citation

Oppenheim, E. Phillips. The Double Traitor. Project Gutenberg, 2003.

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