A working life: The tennis umpire | Work & careers | The Guardian
The U.S Open replaces human line judges with optical technology : NPR
Putting It All on the Line at the U.S. Open - WSJ
Commentary: Tennis technology erases John McEnroe-esque fun - Los Angeles Times
Softball terminology and referee signals
Tennis Ball Out Call Stock Photo - Download Image Now - Tennis, Referee, Fan - Enthusiast - iStock
Tennis umpire hi-res stock photography and images - Alamy
Worst line calls and umpire decisions in Tennis - YouTube
Umpires Hand Signals
You can't be the player's friend': inside the secret world of tennis umpires | Tennis | The Guardian
Kader Nouni: The Umpire Known as the 'Barry White of Tennis' - The New York Times
8,053 Tennis Referee Photos and Premium High Res Pictures - Getty Images
All About Cricket
Tennis Referee Chair Umpire Stock Photos - Free & Royalty-Free Stock Photos from Dreamstime
Carlos Ramos, Umpire Known for Rigidity, Lands in U.S. Open Firestorm - The New York Times
Serena Williams' U.S. Open penalties spark debate over sexism in sports
Djokovic snaps at Wimbledon chair umpire en route to Week 2
Who is US Open tennis umpire Marijana Veljovic? | The US Sun
Serena Williams calls out sexism in tennis | The Chatterbox
Serena Williams had crazy outburst at US Open after calling umpire "liar" and "thief" - Mirror Online
Merlin | Philosophy Referee Hand Signals
Tennis player umpire pictogram icon. A set of pictogram representing tennis, player, serve, stroke, ball boy, line judge, | CanStock
