Explaining Antonio Brown's helmet issue: What are the NFL's rules, Raiders' options, AB's contract?
Know the Safest NFL Helmet Brands: Riddell, Schutt, VICIS, Xenith – newhelmets
Why aren't more football players wearing the safest possible helmet?
Building a safer football helmet, Waterloo News
NFL's Safest Helmets Absorb Impact With 3D Printing Instead Of Foam
Future of football safety could come down to research at Riddell
Football helmet with liquid padding may prevent concussions
NFL awards a Montreal start-up $550,000 to work on its design for a safer football helmet
The Safest Football Helmet Is Not Yet a Hit in the NFL - WSJ
Find out how modern football helmets attempt to limit brain injuries
NFL approves QB-Specific helmet to help quarterbacks keep their heads in game - Hindustan Times
Vicis Ran Out of Cash and Lost Its Founders but Is Still Making Super Bowl-Ready Helmets
Building a better helmet - The Globe and Mail
Riddell's Axiom could be breakthrough helmet for football