Official (gridiron football) - Wikipedia
NFL players will all be tracked by RFID chips this season
Football Zebras - Analysis and commentary of the NFL's officials
Football Zebras - Analysis and commentary of the NFL's officials
WILL INSTANT REPLAY TRIP THE REF? - The New York Times
Overreactions from Steelers Nation: NFL officiating and how to fix
The NFL has an instant replay camera problem
The NFL's Brewing Information War - The Ringer