Constructive proof of the Kerr-Newman black hole uniqueness: derivation   of the full solution from scratch
  The Kerr-Newman black hole solution can be constructed straightforwardly as the unique solution to the boundary value problem of the Einstein-Maxwell equations corresponding to an asymptotically flat, stationary and axisymmetric electro-vacuum spacetime surrounding a connected Killing horizon. 
Reinhard Meinel and Ren\'e Richter
gr-qc astro-ph.HE hep-th