NFL and players' union approve helmet designed to reduce QB concussions, NFL
Heads Up! New helmet getting tryout at NFL minicamps
Everything you need to know about the NFL's helmet guidelines and restrictions - Canal Street Chronicles
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
NFL to test new position-specific helmet designed for pros - The Boston Globe
NFL at 100: Helmets go high tech in quest for player safety
Joe Burrow switches to the new quarterback-specific helmet from Vicis - NBC Sports
Built By Data: NFL Helmet Innovation
NFL Helmet Challenge: Increasing player safety, nTop