It's Unanimous: Mariano Rivera Is a Hall of Famer - The New York Times
Roberto Clemente's legacy celebrated in N.Y., Puerto Rico
Puerto Rican players follow Pirates' push to wear No. 21, celebrate Roberto Clemente
Altoona Curve to retire Roberto Clemente's No. 21
MLB celebrates Roberto Clemente Day, ceremony at Citi Field
Roberto Clemente: Baseball Rebel – Society for American Baseball Research
Roberto Clemente's addition to MLB: The Show a momentous occasion - Our Esquina
Roberto Clemente's death 50 years ago forever changed his son, a former Phillies minor leaguer
Curve Set to Retire No. 21 In Honor of Roberto Clemente
Major League Baseball marks Roberto Clemente Day with ceremony at Citi Field - ESPN
Here's why it would be a bad idea for MLB to retire Roberto Clemente's No. 21
Roberto Clemente, Biography, Stats, & Facts