Do AL and NL MLB umpires wear a patch on their hats for their league? - Quora

How do baseball players view professional umpires? Do they see them as professionals dedicated to upholding the rules of the sport, or as biased, non-athletic observers? - Quora

What is the strike zone in MLB? Why does it change from umpire to umpire? - Quora

Are there different umpires for the American and National League? - Quora

Marlborough's Jim Reynolds calls it a career after 24 years as an MLB umpire - The Boston Globe

Do AL and NL MLB umpires wear a patch on their hats for their league? - Quora

Can an MLB umpire really tell where the ball crosses the plate without taking into account where the catcher's glove is when he catches it? - Quora

I'm a new umpire. What do I need to know about umpire equipment/uniform? - Quora

Meet Mark Lollo, Inventor of the Dry-Lo Umpire Ball Bag, Blog

What do MLB umpires do in the off-season? - Quora

MLB Rules: What do MLB Pitchers have in their hats?

Who's the most famous umpire from the MLB? - Quora

Where can I find cheap, customizable baseball hats with no minimum order? - Quora

Umpire Substance Checks Put Pitchers in Awkward Positions - The New York Times