NFL: 49ers' Willis to undergo season-ending surgery
Patrick Willis retiring from 49ers after injury-shortened season, NFL
The Life And Career Of Patrick Willis (Story)
Time to re-assess Patrick Willis's turf toe injury - Niners Nation
49ers' Patrick Willis lost for season (w/video)
Kaepernick fumbles into end zone as Rams shock Niners, 13-10
49ers LB Patrick Willis retiring after injury-shortened season – New York Daily News
Patrick Willis, American Football Wiki
Patrick Willis will be game-time decision for 49ers – The Mercury News