Late flags seem shady, but in at least one instance referees have no choice
Patriots' Bill Belichick delights fans with demeanor as he slams challenge flag onto ground
NFL Sky Judge: How the New Process Works + Impact on Games
NFL playoff officiating decisions - What happened on controversial calls -- right and wrong -- and what came next - ESPN
Missed calls aplenty, and the NFL is looking for fixes
75 Years Later: The Inspiration Behind the Penalty Flag
The Winners and Losers of Thanksgiving Day Football - The Ringer
Former Cowboys QB Troy Aikman says reviewing pass interference has sent the NFL down a 'slippery slope'
Detroit Lions: Remember the time Jim Schwartz threw that challenge flag?