EXPLAINER: NFL using helmet caps for player safety, research
Guardian Caps Guardian Sports
NFL medical director wants better solutions to concussion cases
More padding the issue of concussions and better helmets
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play, OK'd for Practice - Core77
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
UGA football outfits players in Guardian Caps to try to reduce impacts.
The Coat of Arms Discussion: How are Serious Concussion Issues Changing Football?
Quarterback-specific helmet to be available during 2023 NFL season
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
NFL players don Guardian Caps, designed to protect from concussion
If a player wanted to wear a Guardian Cap during a game, the league would prohibit it