This Helmet Will Save Football. Actually, Probably Not. - The New York Times
Helmet-to-helmet collision - Wikipedia
The Myth of Concussion-Free Football Helmets
Two New Football Helmets Do Battle Against Concussions
About the Book Both ESPN investigative reporters, the authors reveal how the NFL, over a period of nearly two decades, sought to cover up and deny mounting evidence of the connection between football and brain damage. This narrative moves between the NFL trenches, America's research labs and the boardrooms where the NFL went to war against science; it examines how the league used its power and resources to attack independent scientists and elevate its own flawed research.
League of Denial: The NFL, Concussions, and the Battle for Truth [Book]
What Pros Wear: Top 5 Helmets Rated by the NFL & NFLPA - What Pros Wear
NFL and players' union approve helmet designed to reduce QB concussions, NFL
Football helmets have improved but are far from 'concussion proof' – San Bernardino Sun
NFL Looks to Helmet Technology to Combat Concussions