Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
Football helmets have improved but are far from 'concussion proof' – Orange County Register
Football Helmets and Concussion: Equaling the Playing Field - Advancing Your Health
Revolutionary new ZERO1 football helmet may help NFL players reduce concussions
New Football Helmet Could Save the Sport
In Race to Develop Safer Football Helmets, Many Questions Remain - The New York Times
Concussions are a huge issue in football. Outer-padded helmets could go a long way toward solving it. - ESPN
Helmets act like a car bumper to protect your brain
Concussions from top-of-head impact 'more severe'