Guardian Caps Guardian Sports
Flexible NFL helmet aims to reduce head injuries
Leatherhead to Radio-head: The Evolution of the Football Helmet, Arts & Culture
3 in 4 Youth Football Players Have Ill-Fitting Helmets, Posing Concussion Risk
Do helmets protect against concussion? - Queensland Brain Institute - University of Queensland
Wearing headgear for sport does not protect against concussion, Australian experts warn, Concussion in sport
Dal's high-tech football helmets can help detect concussions from the sidelines
Helmets, mouthguards: Is there 'concussion-proof' equipment for fall sports?
New helmet design can deal with sports' twists and turns
Study: Better Football Helmets Needed to Prevent Concussions - Physical Therapy Products
Could magnets in helmets reduce football concussions?, Science
Football helmets do little to protect from concussions