The Moment Madden NFL Killed NFL 2K Forever
Madden NFL 18, PlayStation Wiki
The Evolution of Advertising in Sports Video Games
ESPN NFL 2K5 Review - GameSpot
NFL 2K3 (2002) - MobyGames
ESPN NFL Football - Wikipedia
Blitz: The League - Wikipedia
Madden NFL 11 Ian Cummings Interview by GameSpot
ESPN NFL 2K5 (2004) - MobyGames