More players are calling it quits in prime of their careers, Sports
Why a Bay Area football star gave up his NFL dream for blue-collar job
Patrick Willis Explains Decision to Retire from NFL
Has there been another NFL player that was very talented that retired at an earlier age than Andrew Luck? - Quora
The NFL as it is Known is Not Sustainable - Canal Street Chronicles
Linebacker Patrick Willis is ready to retire, even though he's only 30 – The Denver Post
Patrick Willis Explains Decision to Retire from NFL
Who is the fastest player in the NFL today? - Quora
Retired 49ers lineman Joe Staley hailed by Willis, ex-teammates
The Life And Career Of Patrick Willis (Story)