History of retired numbers dates back to Lou Gehrig Day

On This Day, July 4: Lou Gehrig announces retirement

Lou Gehrig Day June 2 to raise ALS awareness

Jeter's retirement marks end of Yanks' single-digit numbers

Derek Jeter's No. 2, Last of Yankees' Single Digits, to Be Retired - The New York Times

Washington Rush Baseball - DID YOU KNOW? Lou Gehrig's #4 was the first jersey number ever retired. The Yankees retired the Iron Horse's iconic number on July 4, 1939 -- the same

Yankees retired numbers and the baseball legends who wore them

Yankees Retired Numbers

Lou Gehrig MLB Career and Early Life, The Iron Horse

A number of nuggets about retired numbers around the Major League

Every MLB team's retired numbers

Lou Gehrig, Biography, Statistics, Disease, & Facts

Yankees retired numbers