28 % of NFL Players Suffer Brain Trauma
49ers Wunderkind Retires After 1 Year, Brings Concussion Issue
Chris Borland paying San Francisco 49ers back 3/4 of his bonus - ESPN
San Francisco 49ers Chris Borland Retiring at 24, News
Borland Retirement: Is 24 Too Late to Stop Football Brain Damage?
Chris Borland talks 'early' retirement in UW-Madison guest lecture
Chris Borland retires: What can NFL do about its concussion
Chris Borland to pay back part of signing bonus
Another young NFL player calls it quits to protect future health
No regrets for Chris Borland after walking away from 49ers
Madden: No matter the injuries or changes, football will never be in
League of Denial Update NFL Player Quits over Concussion
Borland Not Eager To Wave Early Retirement Banner, But Could Have
Q&A with Chris Borland on the future of football, brain injuries and
Chris Borland's decision to retire from NFL at age 24 admirable