Retired Uniform Numbers in the American League
Power of Derek Jeter's No. 2 - MLB's most productive jersey numbers
Derek Jeter's No. 2, Last of Yankees' Single Digits, to Be Retired - The New York Times
Retired Uniform Numbers in the National League
On the Yankees, retired numbers and a solution in search of a problem
Last player to wear No. 42 for each MLB team
NBA jersey retirements: Kobe's two numbers, Jordan's jersey in Miami without playing and other curiosities
Every MLB team's retired numbers
Eagles Question of the Day: How do you feel about the team's unofficial retired jersey numbers? - Bleeding Green Nation
Some MLB Players Wearing #21, All Wearing 21 Patches Today for Roberto Clemente Day – SportsLogos.Net News
History of retired numbers dates back to Lou Gehrig Day
Eagles Question of the Day: How do you feel about the team's unofficial retired jersey numbers? - Bleeding Green Nation
NFL on CBS - If the #NFL were to retire any player's
Retired Uniform Numbers in the National League