49ers' inability to run the ball frustrates coach Mike Singletary
Patrick Willis Explains Decision to Retire from NFL
John Taylor, Patrick Willis named to 49ers' Hall of Fame
49ers' Patrick Willis retires 'happy' – The Mercury News
49ers' Patrick Willis retires 'happy' – The Mercury News
QB future of all 32 NFL teams: Aaron Rodgers, Tom Brady and other
Patrick Willis Explains Decision to Retire from NFL
49ers Patrick Willis retiring after injury-shortened season
Report: 49ers expect Patrick Willis to retire