The Evolution of the Hard Hat - The New York Times
Uniforms and Personal Gear - Cap | Canada and the First World War
R25A-23 WW1 Imperial Russian Army Officers Visor Hat Green Wool Size 7 1/8 | eBay
How the Military Helmet Evolved From a Hazard to a Bullet Shield | At the Smithsonian| Smithsonian Magazine
British WWI Officer Service Dress Peaked Cap- Size US 7 1/4 (58cm)
Belgian steel helmet | NZHistory, New Zealand history online
Amazon.com: warreplica WW1 Canadian/British Trench Cap and Badge - Reproduction (Size 56 CMS) Khaki: Clothing, Shoes & Jewelry
Combat helmet from World War I used by the 93rd Infantry Division | National Museum of African American History and Culture
Pickelhaube - Wikipedia
Bashford Dean and the Development of Helmets and Body Armor during World War I | Essay | The Metropolitan Museum of Art | Heilbrunn Timeline of Art History
National Museum of the Marine Corps - Artifact Highlight - WWI 2d Division Helmet circa 1918 This M1917 helmet belonged to Marine Arthur E. Lyng. Lyng was a Navy Cross and Distinguished
Brodie Helmet / Helmet, steel, Mark I (World War I) - YouTube