Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
What is a Guardian Cap? Meet the NFL's newest safety measure
NFL hopes to reduce head injuries with 'goofy' helmet experiment
Puffy Guardian Caps Could Reduce NFL Player Concussions
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
Could Guardian Caps be used during NFL games for player safety?, Pro Football Talk
NFL hopes to reduce head injuries with helmet experiment
NFL hopes to reduce head injuries with helmet experiment – The Morning Call
NFL announces more steps to reduce head injuries
First QB helmet designed to help reduce concussions approved by NFL, NFLPA
NFL hopes to reduce head injuries with helmet experiment
NFL reports reduction in concussions among players who wore Guardian Caps in preseason - The Athletic