Clemente Award winners will have 21 on caps for entire MLB career
MLB - Today and every September 15th going forward, we will celebrate the life and legacy of Roberto Clemente. #ClementeDay
All Pirates Wearing #21, Rest of MLB Wears Patches in Honour of Roberto Clemente – SportsLogos.Net News
MLB celebrates former Pirates great Roberto Clemente Day
Roberto Clemente, Pittsburgh's Hero
Roberto Clemente Day: MLB expands list of who can wear No. 21 to Pirates, Puerto Rican players, award nominees
Roberto Clemente - Wikipedia
MLB's Pirates To Honor Roberto Clemente By Wearing His Number
All Puerto Rican players can wear 21 on Clemente Day
Puerto Rican Twins don No. 21 in tribute to Roberto Clemente – Twin Cities