Bill Belichick has some historic NFL ties (and hats), and other thoughts - The Boston Globe
Patriots 38, Browns 15: Bailey Zappe, Tyquan Thornton shine as Bill Belichick makes history
Pompei: Talking to George Halas on the eve of a Bears' playoff game - The Athletic
George Halas — Father Of The NFL Big Blue View
Chicago Bears, American Football Database
Michael McCaskey, who succeeded Halas as Bears' leader, dies
Throwback: The truth about George Halas and the NFL's ban on black players - Windy City Gridiron
George Halas: Father of the NFL Who Also Served in Both World Wars
George Halas: Father of the NFL Who Also Served in Both World Wars
Then Ditka Said to Payton. . .: The Best Chicago Bears Stories Ever Told by Dan Jiggetts, eBook
Halas, the Father of the NFL - Dawgs By Nature
Where did Washington Commanders come from? Here's the story behind every NFL team name
George Halas: Bears architect still going strong at 82 - Sports Illustrated Vault
Front Office Chicago Bears Official Website
With Patriots' win over Browns, Bill Belichick ties George Halas for second-most overall victories - The Boston Globe