Alabama graduate on officiating crew for Super Bowl LII
Why the NFL renamed the 'head linesman' the 'down judge'
American football - Wikiwand
What do the letters stand for on the back of football referees' shirts? - Quora
What is the difference between a linesman and a referee? - Quora
Sarah Thomas makes more NFL history as first female on-field official in playoff game
Sarah Thomas will be line judge as NFL's first full-time female game official – San Bernardino Sun
Refs have to really make the grade to officiate Super Bowl
NFL History of Officiating: A Look at How the Game has Changed - OnFocus
Official (gridiron football) - Wikipedia