Yankees help pay tribute to former Pirates great Roberto Clemente - Newsday
Rangers, MLB honor late Hall of Famer Roberto Clemente with uniform patch, jersey numbers
Pittsburgh Pirates, New York Mets players, coaches to all wear No. 21 on Roberto Clemente Day - ESPN
MLB allows more players to wear No. 21 to honor Roberto Clemente – NBC Sports Chicago
MLB expands list of who can wear No. 21 to honor Roberto Clemente on Sept. 15 - ESPN
Nats DH Cruz, other Clemente Award winners wear '21' on caps
21: The Story of Roberto Clemente: 9781560978923: Santiago, Wilfred: Books
Pittsburgh Pirates, New York Mets players, coaches to all wear No. 21 on Roberto Clemente Day - ESPN
Pirates celebrate Roberto Clemente Day 2020