Jeter returns as Yankees honor 1998 team at Old-Timers' Day, Boone booed by some
New York Yankees: 5 numbers that need to be un-retired
Yankees retired numbers: A look at all of the jersey numbers players cannot wear in the Bronx
Yankees to retire Paul O'Neill's No. 21 jersey this summer - Newsday
Yankees retire Paul O'Neill's No. 21 jersey, Cashman booed
New York Yankees retired Paul O'Neill's No. 21 jersey
Yankees to retire Paul O'Neill's No. 21: See the complete list of retired numbers
Derek Jeter's No. 2 retired: See all New York Yankees retired numbers
Where Derek Jeter ranks among Yankees' retired single-digit numbers
As Paul O'Neill's No. 21 Is Retired, One Last Kick of a Water Cooler - The New York Times
A number of nuggets about retired numbers around the Major League
New York Yankees Retired Numbers Vinyl Decal Stickers