Appreciating the retired single-digit numbers of the New York Yankees
List of New York Yankees captains - Wikipedia
NY Yankee Paul O'Neill's No. 21 to be retired on Aug. 21
A pitcher wearing number 1? It's happened before – Washington baseball history
New York Yankees Retired Numbers - Sports Illustrated
Yankees make major request to MLB due to unique problem
Yankees: Who Will Be The Next Player To Get Their Number Retired? - Unhinged New York
The only day MLB players can wear No. 42? Jackie Robinson Day
Uniform number (Major League Baseball) - Wikipedia
The Worst Players to Wear Each of the 21 Retired Yankees Numbers - Sports Pickle