APA (7th ed.) Citation

Piper, H. B. (2006). The Mercenaries. Project Gutenberg.

Chicago Style (17th ed.) Citation

Piper, H. Beam. The Mercenaries. Project Gutenberg, 2006.

MLA (9th ed.) Citation

Piper, H. Beam. The Mercenaries. Project Gutenberg, 2006.

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