Chris Borland's early retirement shifts focus of head injuries in NFL - Los Angeles Times
NFL star Chris Borland quits over head injury concerns - CBS News
Chris Borland retiring due to concerns about head trauma - Niners Nation
NFL Player Chris Borland Retires Due to Concussion Risk
49ers' Borland retires after rookie year over head trauma fears – Santa Cruz Sentinel
San Francisco 49ers Chris Borland retires over repeated head trauma
Concussion Concern: LB Retires After One NFL Season
Top NFL Rookie to Retire, Citing Concussion Risk
49ers hit hard after unexpected offseason departures - The Boston Globe
No regrets for Chris Borland after walking away from 49ers
Chris Borland's early NFL retirement has led to impact off the field - BVM Sports
San Francisco 49ers Chris Borland Retiring at 24, News
Chris Borland retires from 49ers after one year due to fears over head trauma, NFL
NFL Player Chris Borland Retires Due to Concussion Risk
Chris Borland stuns 49ers with retirement announcement