Major League Baseball expands 'robot umpire' use throughout all 30 Triple-A ballparks
Embattled umpire Ángel Hernández alleges MLB altered evaluations to hurt minorities
The Official 2020-2021 MiLB Umpire Uniform, Blog
Umpire Substance Checks Put Pitchers in Awkward Positions - The New York Times
2023 MLB Uniform Rankings
Umpire-Empire.com
Joe West retires as umpire after record 5,460 games; Roberto Ortiz becomes first Puerto Rican to be full-time ump - ESPN
Umpire (baseball) - Wikipedia
Explaining the FTX Patch worn by MLB Umpires – SportsLogos.Net News
2022 MLB Uniforms - Professional - Umpire-Empire
MLB, Official Information, Umpires