Helmet sensors become mandatory equipment in Arena Football League
Football helmets don't provide much protection from concussions, study suggests - CBS News
NFL Puts Up $3 Million to Find Out Who Can Build a Better Helmet - Bloomberg
Football helmet with liquid padding may prevent concussions
Can the Q-Collar Save Football From Its Concussion Problem? - InsideHook
Big Changes To NFL Helmets Coming Soon? - Daily Norseman
Explaining NFL's new helmet rule: FAQs about league's 'culture change'
Bennet Omalu, Concussions, and the NFL: How One Doctor Changed Football Forever
More padding the issue of concussions and better helmets