Guardian Caps: Why some NFL players are wearing them in training camps
New devices, practice habits aim to curb concussions in high school football
Oklahoma Sooners Continue to be Proactive in Player Safety With Guardian Caps - Sports Illustrated Oklahoma Sooners News, Analysis and More
NFL reports reduction in concussions among players who wore Guardian Caps in preseason - The Athletic
NFL makes Guardian Caps mandatory for many positions through second preseason game - NBC Sports
What's up with the weird helmets? - OUInsider
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play, OK'd for Practice - Core77
Oklahoma Sooners Continue to be Proactive in Player Safety With Guardian Caps - Sports Illustrated Oklahoma Sooners News, Analysis and More
How UVA's use of Guardian Caps helped clear them for The NFL
Guardian Cap Debuts at NFL Training Camps League-wide
NFL: Damar Hamlin & Tua Tagovailoa - What has been learned about player safety? - BBC Sport
Arizona Cardinals defensive end J.J. Watt not fan of the new league-mandated Guardian Caps on helmets
Eagles players on Guardian Caps: 'We look a little goofy,' but all for safety