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Caltrop - Wikipedia
The Caltrop: A Weapon That's Barely Changed Over 2,300 Years
Medieval Weapons: Caltrops. Types of Caltrops, Facts and History
Caltrops | Historic Jamestowne
The Caltrop a Very Important Medieval Weapon
Spiked Defenses: The Tactical Use of Caltrops in Medieval Warfare
Water caltrop - Wikipedia
Caltrop (Tire Spike) - CIA - The World Factbook
Caltrop Weapons - Medieval Chronicles
CALTROP Definition & Meaning | Dictionary.com