Organisation for Economic Co-operation and Development & ProQuest (Firm). (2009). Poland. Organisation for Economic Co-operation and Development.
Lua i Stíl Chicago (17ú heag.)Organisation for Economic Co-operation and Development agus ProQuest (Firm). Poland. Paris: Organisation for Economic Co-operation and Development, 2009.
Lua MLA (9ú heag.)Organisation for Economic Co-operation and Development agus ProQuest (Firm). Poland. Organisation for Economic Co-operation and Development, 2009.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.