@misc{12566,
  author = {Kent-Andre Mardal and Bj{\o}rn Nielsen},
  title = {Efficient Preconditioning of Optimality Systems With Non-Self-Adjoint State Operators},
  year = {2013},
  journal = {IFIP 2013, minisymposia Preconditioning for PDE-Constrained Optimization, Linz, Austria},
}