Do NFL players have headphones in their helmets? - Quora
Vicis pulls concussion-resistant helmets from UW camp - Sports Illustrated
Heads up! New helmet getting tryout at NFL minicamps
The NFL calls Vicis Zero1 helmets the safest yet
Nflpa - Bio, News, Photos - Washington Times
Dallas-Fort Worth high school helmets and concussions
James Sauerbaum on LinkedIn: VICIS x Carbon
Do NFL players have numbers on their helmets? If so, why? - Quora
Behold: The First Position-Specific Football Helmet
For down stances: Is this the end of the line? - Sports Illustrated