An analysis of nearly 4 million pitches shows just how many mistakes umpires make
In Defense of Umpires: Why Complaints About MLB's 'Ump Show' Problem Miss the Mark, News, Scores, Highlights, Stats, and Rumors
Umpire: What Is It? and How to Become One?
Many Roles of the Sports Official - MAC Umpires
The MLB Umpires Association is a flawed and opaque organization - Bleed Cubbie Blue
Baseball: A trip through time with former MLB umpire Bill Hohn – The Times Herald
Sarah Thomas is set to officiate the Super Bowl. How long until a woman becomes an MLB umpire?
Why is MLB still using 6 umpires in postseason games? - Bleed Cubbie Blue
MLB asking umpires for more checks of pitchers for sticky substances
MLB Umpires Missed 34,294 Ball-Strike Calls in 2018. Bring on Robo-umps?, Bostonia
MLB umpires are good at calling balls and strikes, but they need help - The Washington Post
What does an MLB home plate umpire wear for protection? - Quora