Guardian Caps: NFL's hotly debated new safety measure here to stay?
Why Utah players wore Guardian Caps during camp - Deseret News
NFL players experimenting with 'Guardian Caps' to prevent head injuries
NFL: Concussions dropped by more than 50% among players who wore Guardian Caps during summer
Coverage of the NFL in Guardian Caps
The story behind those soft-shell puffy Guardian Caps players have been wearing
Concussions among players who wore Guardian Caps over summer dropped more than 50%, NFL says - ESPN
Chicago Bears: Why players are wearing padded helmets