Organisation for Economic Co-operation and Development. Working Party on Environmental Performance, ProQuest (Firm), & Omersu, G. (2012). Germany 2012. OECD.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Organisation for Economic Co-operation and Development. Working Party on Environmental Performance, ProQuest (Firm), و Gerhard Omersu. Germany 2012. [Paris]: OECD, 2012.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Organisation for Economic Co-operation and Development. Working Party on Environmental Performance, et al. Germany 2012. OECD, 2012.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.