Guardian Caps: Why some NFL players are wearing them in training camps
Why are some Titans players wearing Guardian Caps during training camp?, Titans
Guardian Caps: NFL requires use of helmet cover at training camps to reduce head injuries
Guardian cap' to prevent head injuries mandated for practices, CFL says
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
John's Journal: Park Football Team Is All In On Concussion Safety, News
NFL concussion data could lead to broader use of Guardian Caps - NBC Sports
Guardian Cap - Soft-Shell Protective Helmet Cover : Football Helmets : Sports & Outdoors
Queen's Football utilizing Guardian Caps - Queen's University Athletics
Guardian Caps', NFL's Most Recent Attempt At Preventing Head Injuries