NFL hopes to reduce head injuries with helmet experiment
Louisiana Football Helmets Help Keep Players Cool - ASME
Coverage of the NFL in Guardian Caps
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
Louisiana Football Helmets Help Keep Players Cool - ASME
Guardian Caps Guardian Sports
Armor on the Field: The NFL's Headlong Race to Build the Unbreakable Linebacker
Future of NFL safety: Inside Vicis' high-tech football helmet production facility in Seattle – GeekWire
What Pros Wear: Top 5 Helmets Rated by the NFL & NFLPA - What Pros Wear
Report: More than 100 diagnosed concussions left out of NFL studies, including injuries to ex-Cowboys QB Troy Aikman
Wearing No. 21 just like dad, safety Shilo Sanders leads Colorado's defense into game at Oregon – The Journal
Football helmets are creating more problems than they solve