Breaking down the NFL's 6 new rules for 2021 season - Pride Of Detroit
Uniform number (American football) - Wikipedia
NFL likely to pass rule allowing more single-digit jersey numbers
NFL rule changes for 2021; jersey number expansion
NFL Teams Debuting Alternate Helmets, Jerseys for the 2022 Season – NBC Los Angeles
NFL jersey numbers: The best player to wear all 101 options
NFL taunting explained: Point of emphasis, rule change, fines – NBC Sports Chicago
Tom Brady Eviscerates NFL Over New Jersey Number Rule Change, 'DUMB'
The NFL Jersey Number Rule Explained - HowTheyPlay
NFL CBA approved - What players get in new deal, how expanded playoffs and schedule will work - ESPN
The NFL's new single-digit jerseys are inspiring excitement and a little grumbling - The Washington Post