The eta mass and NNLO Three-Flavor Partially Quenched Chiral   Perturbation Theory
  We show how to resum neutral propagators to all orders in Partially Quenched Chiral Perturbation Theory. We calculate the relevant quantities to next-to-next-to-leading order (NNLO). Using these results we show how to extend the proposal by Sharpe and Shoresh for determining the parameters relevant for the eta mass from partially quenched lattice QCD calculations to NNLO. 
Johan Bijnens and Niclas Danielsson (Lund)