New York Yankees to retire Paul O'Neill's No. 21 on Aug. 21 - The San Diego Union-Tribune
The oldest Yankees' players in history by position - Pinstripe Alley
Report: Jorge Posada will announce retirement within next two weeks - NBC Sports
Best Yankees players by uniform number
After honoring '98 team, Yankees fall to Brewers – Trentonian
Mariano Rivera - Wikipedia
Derek Jeter gives Yankees win at stadium finale
As the Posada Saga unfolds, Boston Red Sox catcher Jason Varitek has words of respect
Derek Jeter hits walk-off single in final Yankee Stadium at-bat
Posada says he won't be back with Yankees in 2012
Jorge Posada - Wikipedia
This Day in Yankees History: Jorge Posada retires from baseball - Pinstripe Alley
Jorge Posada, longtime Yankees catcher, reportedly about to announce retirement
Posada: PED users shouldn't be in HOF