Houston Astros: 8 players don No. 21 on Roberto Clemente Day
Carlos Delgado says MLB should retire Roberto Clemente's No. 21
Tampa Bay Rays honor Roberto Clemente by starting nine Latin American position players - The Boston Globe
Pirates to once again wear No. 21 for Roberto Clemente Day
Roberto Clemente: More than Latin America's baseball star
Sources: MLB letting more players to wear No. 21 for Clemente Day
For the 'Great One'; Pirates, MLB honor Roberto Clemente
Here's why it would be a bad idea for MLB to retire Roberto Clemente's No. 21
Major League Baseball marks Roberto Clemente Day with ceremony at Citi Field - ESPN