NFL number changes: list of players who have switched jersey numbers
NFL passes new jersey rules, will allow more players to wear single-digit numbers
NFL jersey number restrictions could change for running backs, receivers, tight ends, linebackers, defensive backs
Tom Brady slams NFL's jersey number rule: 'Dumb'
Number (sports) - Wikipedia
The NFL's new single-digit jerseys are inspiring excitement and a little grumbling - The Washington Post
NFL likely to pass rule allowing more single-digit jersey numbers
NFL Relaxes Restrictions on Jersey Numbers - The New York Times
Tom Brady explains why he's still mad about NFL's new 'crazy' jersey number rules
How is a player's jersey number decided in football? - Quora