Guardian cap' to prevent head injuries mandated for practices, CFL says
NFL fans react to new guardian cap rules
Equipment To Protect Your Top Commodity - Training & Conditioning
Guardian Cap Debuts at Training Camps League-wide
High schools try to cap concussions
Concussions: Can cap keep football players' heads in game? – Orange County Register
What are those funny-looking soft caps on NFL helmets during camp?, Sports
NFL players wear Guardian Caps to reduce head trauma during training camp
Guardian helmet caps are being used to mitigate concussion issues
Guardian Cap Debuts at Training Camps League-wide
More teams practicing with Guardian Caps, Sports
Guardian Caps: The new helmets worn by several NFL teams
Guardian Caps show promise in tackling concussion concerns in football