New York Yankees history: Paul O'Neill's number 21 must be retired
Aaron Judge and home runs carrying Yankees: Why he must stay
Here are the Yankees' 21 retired numbers
Fresno State to retire numbers of Aaron Judge, Mike Batesole
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Here are the Yankees' 21 retired numbers
Yankees to retire Derek Jeter's No. 2 on May 14 – New York Daily News
How many jersey numbers do the Yankees have left? - Deseret News
Judge hits 3 home runs, becomes first Yankees player to do it