2007 NFL season - Wikipedia
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Pro Football Journal: 1932 NFL MVP Retroactive
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Street & Smith's Pro-Football Yearbook
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Game Plan Pro Football 1979 Annual Preview : GamePlan Magazines : Free Download, Borrow, and Streaming : Internet Archive
Has any player won the Heisman Trophy playing on a losing team? - Quora
Pro Football Journal: 1933 NFL MVP RACE Retroactive
Pro Football Journal: 1934 NFL MVP Retroactive
New York Giants History - Big Blue Interactive
Pro Football Journal: 1929 NFL MVP Retroactive
Pro Football Journal: 1932 NFL MVP Retroactive
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Pro Football Journal: 1936 NFL MVP RACE Retroactive