Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
An examination of the current National Operating Committee on Standards for Athletic Equipment system and a new pneumatic ram method for evaluating American football helmet performance to reduce risk of concussion
Are high school girls' lacrosse players at increased risk of concussion because they are not allowed to wear the same helmet boys' lacrosse players are required to wear?, Injury Epidemiology
Reduces impact up to 33% One size fits all Insulates in hot & cold weather
Guardian Protective Helmet Cover
Concussions: Can cap keep football players' heads in game? – Orange County Register
How do helmets reduce risk of concussion?
In case, like me, you were wondering why Eddie Lacy's helmet had that piece on the front, it's supposed to reduce concussions : r/nfl
Advancements in Football Helmet Technology - Information, resources and guides on Traumatic Brain Injury
Football helmets at Philadelphia-area high schools shed light on growing concussion concerns
How a soft-shell helmet is limiting the risk of concussions at Rutgers football camp
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
The Fruitless Search for a 'Concussion-Proof' Football Helmet - The Atlantic
Football Helmet IP Goes Head to Head – TechPats
GameBreaker In the News : WTOP :: A New 'Soft Shell' Helmet is Geared to Keep Athletes Safe