The ciconia metric on the tangent bundle of an almost-Hermitian manifold
  We find a new class of invariant metrics existing on the tangent bundle of any given almost-Hermitian manifold. We focus here on the case of Riemannian surfaces, which yield new examples of K\"ahlerian Ricci-flat manifolds in four real dimensions. 
Rui Albuquerque
math.DG math.CV math.SG