Calvin Johnson: Lions told him to change concussion story
Sports WebXtra: Lions wide receiver Calvin Johnson retires from NFL
Calvin Johnson - Wikipedia
Detroit Lions Star Wide Receiver Calvin Johnson Unexpectedly Retires
Lions star WR Calvin Johnson, 30, retires after 9 seasons
Calvin Johnson, Quiet and Classy, Retires the Way He Played - The New York Times
Lions WR Calvin Johnson Mulls Retirement; Could the Patriots Save Him? - Pats Pulpit
Vikings React to Calvin Johnson's Retirement
Bell: Only the NFL grind could stop Calvin Johnson
Lions WR Calvin Johnson retires from NFL – New York Daily News
Detroit's Calvin Johnson could have played his last snap in the NFL, NFL News
Detroit Lions: Calvin Makes Statement About Decision to Retire