MLB umpires are good at calling balls and strikes, but they need help - The Washington Post
10 Secrets of MLB Umpires
Ump files racial discrimination suit against MLB
Rung Up: Are Postseason Umpires Actually Baseball's Most Accurate?
Gerry Davis Joins Little League® Team as Senior Umpire Consultant - Little League
MLB umpire job responsibilities
Earning Their Stripes as Umpires and Referees - The New York Times
MLB asking umpires for more checks of pitchers for sticky substances
If you aren't a white male, YER OUT of luck as an umpire - Global Sport Matters
Will robo umpires be the end of the game as we know it? (SB Nation Reacts) - AZ Snake Pit
10 Secrets of MLB Umpires