Cleaver, K. M., & Schreiber, G. A. (1994). Reversing the spiral: The population, agriculture, and environment nexus in Sub-Saharan Africa. World Bank.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Cleaver, Kevin M., و Götz A. Schreiber. Reversing the Spiral: The Population, Agriculture, and Environment Nexus in Sub-Saharan Africa. Washington, D.C.: World Bank, 1994.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Cleaver, Kevin M., و Götz A. Schreiber. Reversing the Spiral: The Population, Agriculture, and Environment Nexus in Sub-Saharan Africa. World Bank, 1994.