Certain NFL players must wear Guardian Caps through second preseason game
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
Could Guardian Caps be used during NFL games for player safety?, Pro Football Talk
Guardian cap' to prevent head injuries mandated for practices, CFL says
As NFL mandates Guardian caps in practice, area high school football teams have been using them for years, Sports
Padded helmet cover shows little protection for football players - Scope
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
What Pros Wear: Guardian Caps What are Those Helmet Covers Being Worn in Practice? - What Pros Wear
Guardian Caps Guardian Sports
Park High School football blazes safety trail with Guardian Caps
NFL playoffs 2022: Which bubble teams can sneak into the field?, NFL
EXPLAINER: NFL using helmet caps for player safety, research
Concussions: Can cap keep football players' heads in game? – Orange County Register