Chicago Bears - Wikipedia
John Happenny – Society for American Baseball Research
George Halas was a pro basketball pioneer as well
History of the Chicago Bears - Wikipedia
Chicago Bears founder George Halas played a part in everything for NFL - Chicago Sun-Times
Who is George Halas? Looking back at the former Chicago Bears owner
The Story of “Papa Bear” George Halas - University of Illinois Athletics
NFL star George Halas was once a Yankee
Chicago Bears, History & Notable Players
Uncle Mike's Musings: A Yankees Blog and More: How to Be a Met Fan In Chicago -- 2019 Edition