John Madden Football [1989] [Articles] - IGN
John Madden Football (Video Game 1988) - IMDb
How John Madden Became the Face of a Video Game Empire - The New York Times
Madden NFL 19: The weird story behind the first 'John Madden Football' game
EA Sports' Madden series celebrates its 30th birthday - Polygon
Gamer God: How Madden became the biggest name in football
John Madden Football II [Articles] - IGN
Madden Football History and EA's Other Notable Genesis Football Games - RetroGaming with Racketboy