Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
Why Alabama football players are wearing padded helmets in practice
Could Guardian Caps be used during NFL games for player safety?, Pro Football Talk
Guardian Caps Guardian Sports
Guardian cap' to prevent head injuries mandated for practices, CFL says
Guardian Caps, a soft-shell helmet cover, among CFL's new player-safety initiatives
EXPLAINER: NFL using helmet caps for player safety, research
Bombers welcome introduction of new safety gear – Winnipeg Free Press
Guardian Caps: What Are They & How Do They Work?
NFL Health and Safety Fact Sheet
New Football Helmet Could Save the Sport
NFL players wear Guardian Caps to reduce head trauma during training camp
Asked and Answered: Aug. 3
As NFL mandates Guardian caps in practice, area high school football teams have been using them for years, Sports
7 Observations From Day 1 Of 2022 Seahawks Training Camp