APA (7th ed.) Citation

Oppenheim, E. P., & Grefé, W. (2011). The Wicked Marquis. Project Gutenberg.

Chicago Style (17th ed.) Citation

Oppenheim, E. Phillips, and Will Grefé. The Wicked Marquis. Project Gutenberg, 2011.

MLA (9th ed.) Citation

Oppenheim, E. Phillips, and Will Grefé. The Wicked Marquis. Project Gutenberg, 2011.

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