Why doesn't college football use helmet communication like the NFL? Inside a new system that could change that - The Athletic
We Can Make Football Safer - Scientific American
NFL faces intense scrutiny over concussion protocols
The NFL Is Considering A Drastic Rule Change That Would Change It's Iconic Image
Sources -- AB says no football without old helmet - ESPN
Meet Four Men Who Broke The NFL's Color Line
NFL Bans Tom Brady's Helmet Style, But QB Will Be Allowed To Wear It In 2018 - CBS Boston
N.F.L. Adopts Helmet Rule and Alters Tuck Rule - The New York Times
Leatherhead to Radio-head: The Evolution of the Football Helmet, Arts & Culture
Shamarko Thomas becomes first NFL player ejected for helmet rule
Everything you need to know about the NFL's helmet guidelines and restrictions - Canal Street Chronicles
No. 2 Michigan romps past Minnesota 52-10 with pair of pick-6s for 17th straight win in Big Ten
The Future of NFL Defenses Lies in a Lime-Green Dot - The Ringer
Unprecedented Rate Of Improvement Stimulated In Helmet Industry, New Standard Set For 'Top-Performing' Helmet Models Worn By NFL Players