NFL concussion protocol: What are the steps for return to play?
CQ Researcher - CTE and Athletes
Doctors and a former NFL athlete talk about the risks and treatments of concussions
Does Your School Protect Your Head? - YR Media
NFL hopes to reduce head injuries with helmet experiment
The Impact Of 'Concussion': High School Football Player Changes Course
Football Players Drill Without Helmets To Curb Concussions
Repeated Head Hits, Not Just Concussions, May Lead To A Type Of Chronic Brain Damage
Football Players Drill Without Helmets To Curb Concussions : Shots - Health News : NPR
Helmets don't eliminate concussions. It's time for the NFL to ditch them, NFL