Chris Borland's retirement: Is an NFL player's brain really more
Chris Borland Retires from NFL at Age 24: Latest Details, Comments
Chris Borland: NFL player quits over concussion fears - BBC Sport
Chris Borland slams Wisconsin football program in Netflix doc
Wary of head trauma, 49ers' Chris Borland retiring at 24
49ers linebacker Borland to retire after one year
49ers Chris Borland retires from football, citing concern over head
How many millions did 49ers' Chris Borland give up by retiring at 24?
49ers' Chris Borland becomes latest young NFL star to retire early
Chris Borland, San Francisco 49ers linebacker, retiring due to
SF's Borland quits over safety issues - ABC News