Flops and Equivalences of derived Categories for Threefolds with only   Gorenstein Singularities
  The main propose of this paper is to show that Bridgeland's moduli space of perverse point sheaves for certain flopping contractions gives the flops, and the Fourier-Mukai transform given by the birational correspondence of the flop is an equivalence between bounded derived categories. 
Jiun-Cheng Chen