APA (7th ed.) Citation

Speer. (1997). Portals to hell: Military prisons of the Civil War. Stackpole Books.

Chicago Style (17th ed.) Citation

Speer. Portals to Hell: Military Prisons of the Civil War. Mechanicsburg, PA: Stackpole Books, 1997.

MLA (8th ed.) Citation

Speer. Portals to Hell: Military Prisons of the Civil War. Stackpole Books, 1997.

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