Singular Monopoles and Gravitational Instantons
  We model A_k and D_k asymptotically locally flat gravitational instantons on the moduli spaces of solutions of U(2) Bogomolny equations with prescribed singularities. We study these moduli spaces using Ward correspondence and find their twistor description. This enables us to write down the K\"ahler potential for A_k and D_k gravitational instantons in a relatively explicit form. 
S.A. Cherkis and A. Kapustin