Tom Brady's helmet model among those banned for 2018 - Sports Illustrated
According To Study, NFL Players Used Low-Rated Helmets - CBS Chicago
Harvard to lead $100m study of NFL players - The Boston Globe
Future of football safety could come down to research
NFL helmet maker helping curb soldiers' head injuries, Sports
Revolutionary new ZERO1 football helmet may help NFL players reduce concussions
Vicis high-tech helmets take top 3 spots in NFL's annual performance ranking of equipment – GeekWire
Varsity Football Helmet Ratings
Helmet market, with deep Detroit ties, in arms race
The Zero1 Flexible Football Helmet May Save Players' Brains
What Pros Wear: Top 5 Best Youth Football Helmets (2020) - What Pros Wear
How football helmets fail to protect against some of the most dangerous hits in the game - The Verge
NFL helmet maker helping curb soldiers' head injuries
NFL hopes to reduce head injuries with helmet experiment