Raiders, other NFL teams wear Guardian Caps for head safety, Raiders News
NFL hopes to reduce head injuries with helmet experiment
Guardian Caps are the latest effort to address CTE, football concussion concerns
NFL Health and Safety Fact Sheet
What are Guardian Caps? NFL's latest padded helmets for added safety
Why guardian caps are now part of practice helmets for certain Titans
NFL CMO Dr. Allen Sills explains importance of mandated guardian caps during training camp
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
Eagles players on Guardian Caps: 'We look a little goofy,' but all for safety