Baseball Hall of Fame: Best player with every uniform number
Yardbarker's Ultimate MLB Hall of Fame tiers
Pedro Martinez beat all the odds in Hall of Fame career – New York Daily News
Predicting every Baseball Hall of Fame class through 2045 - ESPN - SweetSpot- ESPN
MLB allows more players to wear No. 21 to honor Roberto Clemente – NBC Sports Chicago
Ken Griffey Jr. To Join Mariners Hall of Fame, by Mariners PR
The NFL's best players by uniform number: 00–49 - Sports Illustrated
National Baseball Hall of Fame - Dressed to the Nines - Parts of the Uniform
How players are using uniform numbers to break MLB's unwritten rules - ESPN
Puerto Rican Twins don No. 21 in tribute to Roberto Clemente – Twin Cities