History: The Disputed Origins of the Butterfly Knife
The History of the Balisong Knife: Everything You Need to Know - EKnives LLC
From Self-Defense Weapon to Pop Culture Icon: The Evolution of the But – BladesPro US
The History of The Balisong Knife – Knife Pivot Lube
Answering the Question, Are Butterfly Knives Illegal? - Vander Law
The History and Origins of the Butterfly Knife – Squid Industries
From Self-Defense Weapon to Pop Culture Icon: The Evolution of the But – BladesPro US
Sold at Auction: WWII GERMAN THIRD REICH SS BUTTERFLY KNIFE
Sold at Auction: Unmarked Vtg Butterfly Knife
The History and Origins of the Butterfly Knife – Squid Industries