The Safest Football Helmet Is Not Yet a Hit in the NFL - WSJ
NFL helmet rule: Players shouldn't panic about penalties
Helmet safety: Inside the complicated equipment industry - Sports Illustrated
Many Violent Hits Remain Legal Even After N.F.L. Scrutiny - The New York Times
Vicis expands helmet line with new soft 'cap' for practices, 7-on-7 and flag football – GeekWire
Revolutionary new ZERO1 football helmet may help NFL players reduce concussions
How football helmets fail to protect against some of the most dangerous hits in the game - The Verge
NFL Player Safety: The Case for Banning Helmets and Why It Could Make American Football Safer, News, Scores, Highlights, Stats, and Rumors
NFL helmet safety testing results: Vicis ranks first again for its high-tech head protector – GeekWire