O'Reilly, J., and Ward, P. (2011). DRG-based Hospital Payment and Efficiency: Theory, Evidence, and Challenges, Miriam Wiley (Ed.), Diagnosis-Related Groups in Europe: Moving Towards Transparency, Efficiency and Quality in Hospitals, Maidenhead: Open University Press and WHO Regional Office for Europe, https://www.esri.ie/publications/drg-based-hospital-payment-and-efficiency-theory-evidence-and-challenges