Para-Complex Geometry and Gravitational Instantons
  We give a complete classification of supersymmetric gravitational instantons in Euclidean N=2 supergravity coupled to vector multiplets. An interesting class of solutions is found which corresponds to the Euclidean analogue of stationary black hole solutions of N=2 supergravity theories. 
J. B. Gutowski and W. A. Sabra
hep-th