Ewa Klimowicz proof-read the translation into Polish. Isabelle Renaud provided production and administrative support. All requests for public or commercial use and translation rights should be submitted to rights@oecd.org. Requests for permission to photocopy portions of this material for public or commercial use shall be addressed directly to the Copyright Clearance Center (CCC) at info@copyright.com or the Centre frangais d’exploitation du droit de copie (CFC) at contact@cfcopies.com.