NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
NFL players wear Guardian Caps to reduce head trauma during training camp
NFL CMO Dr. Sills on Guardian Caps Mandate >> Guardian Sports
NFL exec suggests Guardian Caps worn to protect players during practices could one day debut in games, National
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play, OK'd for Practice - Core77
Guardian Cap Debuts at Training Camps League-wide
NFL CMO Dr. Allen Sills explains importance of mandated guardian caps during training camp
NFL hopes to reduce head injuries with helmet experiment
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play, OK'd for Practice - Core77
Guardian Cap: What are and why the NFL asks this safety measure in helmets
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets