Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
Football Guardian Cap draws mixed reviews from players, experts for safety effectiveness - The Daily Tar Heel
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
Utah Utes football adds new concussion-reducing helmets for fall camp
What are those funny-looking soft caps on NFL helmets during camp?, Sports
High school football teams go soft in the fight against brain injuries
What are Guardian Caps and how are they helping football teams?
EXPLAINER: NFL using helmet caps for player safety, research
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
More padding the issue of concussions and better helmets
NFL hopes to reduce head injuries with helmet experiment – The Morning Call
Anything we can do to protect them: East Clarendon uses Guardian Caps to protect against concussions - The Sumter Item