NFL will partner with Hawk-Eye to enhance instant replay capabilities and shorten delays
Officiating crews for the 2021 season – Football Zebras
Tackling Tech: An Inside Look at NFL Instant Replay for 2017
John Parry on calling Super Bowl 53, pass interference replay, more - Sports Illustrated
NFL first: About one-fifth of the 124 officials will be made full-time employees this season - Los Angeles Times
Has NFL found answer to fewer challenges with 'replay assistance'?
NFL creates new officiating post: VP of replay and administration – Football Zebras
Upon further review, NFL officiating is in 'decline'
NFL Officials: Preparing for Success
NFL referee assignments Week 9: Who are the officials for every game this week?
NFL Football Operations NFL Football Operations