History of The Football Helmet - Atavus
First QB helmet designed to help reduce concussions approved by NFL, NFLPA
NFL, NFLPA approve concussion-reducing helmet for quarterbacks
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
Jeremy Repanich: Helmets alone won't save football from concussions - Sports Illustrated
Football helmet - Wikipedia
New 'QB-Specific' Helmets Unveiled, Will Kenny Pickett Wear One? - Steelers Depot
NFL & NFLPA approve first position-specific helmet for linemen – New York Daily News
First QB Helmet Designed To Help Reduce Concussions Approved