Dodgers celebrate Fernando Valenzuela's number retirement - Los Angeles Times
Rich tradition of retired numbers part of game's legacy
MLB allows more players to wear No. 21 to honor Roberto Clemente – NBC Sports Chicago
Which pro sports teams have the most retired numbers?
Retired Uniforms by Division: National League West - Beyond the Box Score
History of retired numbers dates back to Lou Gehrig Day
Retired number - Wikipedia
How players are using uniform numbers to break MLB's unwritten rules - ESPN
Fresno State Athletics announces Judge, Batesole jersey retirement - Fresno State
San Diego Padres Retired Numbers Petco Park Insider - San Diego Padres
History of retired numbers dates back to Lou Gehrig Day
Barry Bonds gets closure he always wanted as Giants retire his jersey
List of Major League Baseball retired numbers - Wikipedia
Retired Uniform Numbers in the American League
Every MLB team's retired numbers – NBC Sports Chicago