Football helmets have improved but are far from 'concussion proof
NFL to test new position-specific helmet designed for linemen - ESPN
A brief history of Football helmet technology
NFL at 100: Helmets go high tech in quest for player safety
The safest helmet in football: What's inside the NFL's newest
Will the NFL's Blitz for Position-Specific Helmets Pay Off
The NFL's Quest for a Better Football Helmet - Sports Illustrated
Helmet market, with deep Detroit ties, in arms race
Vicis Pulls Its Own Hi-Tech Helmets From Huskies Football Camp
NFL Says Regular Season Concussions Rose 18%