MLB And Umpires: Inside the MLBUA - Dodger Yard
Contact Us - Association of Minor League Umpires
Are MLB umpires ruining the sport of baseball? - Quora
More Steals, No Shifts and Robot Umps: 'Our Fans Want the Action' - The New York Times
Play ball!': The Diamond hosts MLB umpire camp Saturday, showing off Richmond's baseball culture
Waterdown umpire Chris Marco climbing the minor league ladder
I'm a new umpire. What do I need to know about umpire equipment/uniform? - Quora
Art Williams made history as 1st Black umpire in National League
A “Full-Count Conversation” with Umpires Robbie Guest and Don Brown - Little League
The History of Umpiring
Association of Minor League Umpires