Guardian Caps: NFL requires use of helmet cover at training camps to reduce head injuries
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
NFL Presents: League-wide Guardian Cap Use to Reduce Head Impacts
What are Guardian Caps? NFL's latest padded helmets for added safety
Equipment To Protect Your Top Commodity - Training & Conditioning
Gadd Severity Index scores (mean 6 SD) measured for helmets with or
NFL CMO Dr. Allen Sills explains importance of mandated guardian caps during training camp
Helmets – The Concussion Blog
NFL says positions wearing Guardian Caps saw 52% decrease in concussions - NBC Sports
Waive Budget Neutrality Rules to Protect Patient Access to Specialty Care, Lawmakers Request - Physical Therapy Products
Guardian Cap Results: “Exceeded Our Expectations”
New Football Helmet Could Save the Sport
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play, OK'd for Practice - Core77
Large Bubble Helmets Are Guardian Caps, NFL's New Safety Measure