Beyond the grunt: Umpires mic up, and baseball changes a bit –
MLB umpires wear wristbands to protest 'abusive' treatment
MLB Umpires Missed 34,294 Pitch Calls in 2018. Time for Robo-umps?, BU Today
Former MLB Ump shares insights with Protect the Game trainees - Triple Crown Baseball
MLB umpire rankings: Pat Hoberg is baseball's most accurate ump
Umpire (baseball) - Wikipedia
Madden: Mets' Buck Showalter opens up on the state of pitching
The Ump Show - BallNine
Robo umps reach Triple-A, but Major League Baseball rollout still uncertain - Washington Times