49ers hit hard after unexpected offseason departures - The Boston Globe
49ers' Patrick Willis retires
49ers in flux as Patrick Willis, Justin Smith retire - Sports Illustrated
49ers LB Patrick Willis retiring
49ers great Patrick Willis starts surprising new career in retirement
49ers LB Patrick Willis to retire - ABC13 Houston
49ers: 5 former players who could come out of retirement to play
Patrick Willis Explains Decision to Retire from NFL
49ers LB Patrick Willis retiring after injury-shortened season – New York Daily News