Why are MLB players wearing No. 42 jerseys today?
Retired number, sports award
Houston Astros: 8 players don No. 21 on Roberto Clemente Day
Jackie Robinson Day, MLB Together
Every MLB team's retired numbers – NBC Sports Chicago
Dodgers gather at Jackie Robinson statue to pay respects
USA Softball wears No. 42 on Jackie Robinson Day
The No. 42 All-Star team
MLB allows more players to wear No. 21 to honor Roberto Clemente – NBC Sports Chicago