Exactly How Dangerous Is Football?
Injuries make the NFL a brutal sport. But the violence is partly why fans love it
American football - Wikipedia
Violence at high school football games a nationwide issue amid referee shortage - Sports Illustrated High School News, Analysis and More
Is the NFL too violent to continue as a mainstream sport? - Quora
When sports fans fight: Why violence in the stands, online rage are spreading
A History of Fatal Sports Fan Violence
Numb to Violence? Fans, Maybe, but Not Players - The New York Times
College football - Wikipedia
American football – Travel guide at Wikivoyage
The Decline Of Football Is Real And It's Accelerating
Column: Flag football at the Olympics? It might happen
California rodeo animals face violent and deadly casualties - Los Angeles Times
Is the NFL too violent to continue as a mainstream sport? - Quora