Hughes, G., & Bucknall, J. (2000). Poland: Complying with EU environmental legislation. World Bank.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Hughes, Gordon, و Julia Bucknall. Poland: Complying with EU Environmental Legislation. Washington, D.C.: World Bank, 2000.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Hughes, Gordon, و Julia Bucknall. Poland: Complying with EU Environmental Legislation. World Bank, 2000.