Common NCAA football penalties and referee hand signals - CougCenter
National Football League: The NFL's Officiating Disaster Continues
Officials draw criticism for late calls in Chiefs vs. Vikings, but penalties wouldn't have changed key drive
How Penalties Work in (American) Football
American Football Penalties / Useful Notes - TV Tropes
The N.F.L. Struggles to Tackle Its Latest Problem: Tackling - The New York Times
The Five Most Outrageous Taunting Penalties of the 2021 NFL Season - The Ringer
Browns-Steelers: Video shows refs miss clear penalty on last pass to Donovan Peoples-Jones - Dawgs By Nature
Seeing yellow: The data behind penalties in the NFL
How Are NFL Refs Held Accountable for Their Performance?, News, Scores, Highlights, Stats, and Rumors
Patriots expected Jerome Boger to call more penalties on them than on the Panthers - Pats Pulpit