Calvin Johnson's Experience with the NFL and Traumatic Brain Injury
Calvin Johnson Contemplating Retirement from Lions, NFL
Bacon: Calvin Johnson probably going to retire; Red Wings borderline wild card team
Lions' Calvin Johnson makes 'difficult decision' to retire
Detroit Lions – Reaction to retirement of Calvin Johnson, a 'humble superstar' – The Oakland Press
Calvin Johnson of Detroit Lions retiring from NFL after nine seasons - ESPN
Detroit Lions Star Wide Receiver Calvin Johnson Unexpectedly Retires
Beloved Calvin Johnson was once-in-a-generation talent, and man
When Calvin Johnson retired, he left a Hall of Fame legacy that hopefully won't be forgotten
Calvin Johnson announces his retirement from the NFL - The Washington Post
Calvin Johnson - Wikipedia
Agent: Still no decision on Calvin Johnson's future
Calvin Johnson Speaks About His Retirement, Legacy