Statistical Entropy of Nonextremal Four-Dimensional Black Holes and   U-Duality
  We identify the states in string theory which are responsible for the entropy of near-extremal rotating four-dimensional black holes in $N=8$ supergravity. For black holes far from extremality (with no rotation), the Bekenstein-Hawking entropy is exactly matched by a mysterious duality invariant extension of the formulas derived for near-extremal black holes states. 
G.T. Horowitz, D.A. Lowe and J.M. Maldacena