Chris Borland's Retirement Will Trigger Player Debate On Risk Of Future Dementia
Retiring 49er Chris Borland to pay back NFL signing bonus - Sports Illustrated
NFL Player Chris Borland Retires Due to Concussion Risk
Early retirement: Willis called it quits in his prime
More players are calling it quits in prime of their careers, Sports
Athlete to Educator: Chris Borland wants to talk
Is Chris Borland's retirement the beginning of the end for the NFL? (updated) - The Washington Post
Badgers football: Former UW great Chris Borland retiring from NFL after only one season, citing head injury worries
San Francisco 49ers Linebacker Retires at 24 Over Head-Trauma Fears
NFL: Players call it quits in prime of careers
Athlete to Educator: Chris Borland wants to talk
Roth: Early retirement start of NFL trend