12 shirt numbers that have been retired for strange, sad and symbolic reasons
Wayne Gretzky, Mario Lemieux and Others: The Best Retired Numbers in the NHL, News, Scores, Highlights, Stats, and Rumors
The Pittsburgh Steelers list of unofficially retired numbers
NBA jersey retirements: Kobe's two numbers, Jordan's jersey in Miami without playing and other curiosities
Retired Numbers Oakland Athletics
New York Yankees: The Numbers on the Wall
Kobe Retiring Both Numbers Is So Very Kobe - The Ringer
Would Celtics re-issue retired numbers? Don't count on it – Boston Herald
The 'Lakers retired numbers' quiz
Every MLB team's retired numbers
Alexander: There's no single standard for retired numbers – Orange County Register
Buckley: If it feels right, like with Paul Pierce, retire the number – Boston Herald