United Nations Environment Programme & UNEP. Global Environment Outlook 4: Evironment for development. GEO-4: evironment for development.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)United Nations Environment Programme و UNEP. Global Environment Outlook 4: Evironment for Development. GEO-4: Evironment for Development. UNEP. EARTHSCAN.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)United Nations Environment Programme و UNEP. Global Environment Outlook 4: Evironment for Development. GEO-4: Evironment for Development.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.