Retired number - Wikipedia
Southern California teams' retired numbers – Orange County Register
Bill Russell's No. 6 Joins Rare Class of Retired Jersey Numbers
Retired number - Wikipedia
Albert Pujols retired with an untouchable record that you didn't know
List of National Football League retired numbers - Wikipedia
Cities With the Most Professional Sports Franchises
Washington University to retire Shelby Jordan's number
Average NFL career length
Infographic: Packers' retired numbers
Every MLB team's retired numbers