The CFL has figured instant replay out. How long until the NFL and CFB follow suit? - Footballscoop
The NFL has an instant replay camera problem
History of Instant Replay
NFL Going to Full-Time Booth Replays Would Be Overkill, News, Scores, Highlights, Stats, and Rumors
NFL will consider further instant replay changes, but 'sky judge' remains unlikely : r/nfl
Replay review in gridiron football - Wikipedia
Behind the scenes at the NFL's new replay review center in New York - Sports Illustrated
Instant replay under review next week: NFL Newswatch