What football teams have gone undefeated in NFL history? - AS USA
The Formula That Built the NFL's Breakout Teams - WSJ
10 Absolute Worst NFL Teams Since Expansion
Breaking Down the Remaining Unranked, Unbeaten Teams in College Football - Sports Illustrated
Every last undefeated NFL team since 17-0 Miami Dolphins
Eagles are 8-0, how other undefeated NFL teams fared in history – NBC Sports Philadelphia
How Many NFL Teams Have Gone Undefeated in a Season?