Have the NY Yankees retired too many numbers? - Quora
Yankees want to stop issuing uniform numbers to managers, coaches
Here are the Yankees' 21 retired numbers
Yankees retire Mariano Rivera's number
Derek Jeter's No. 2, Last of Yankees' Single Digits, to Be Retired
Aaron Boone, coaches could lose numbers with Yankees running out
How many jersey numbers do the Yankees have left? - Deseret News
We need to talk about Yankees un-retiring numbers again
Yankee Retired Numbers: The All-Time Numerical Lineup of Yanks