توثيق جمعية علم النفس الأمريكية APA (الطبعة السابعة)

E., H. (1967). Trends in the World Demand for Primary Products & Their Impli-cations for the Exports of De-veloping Countries. The Institute of National Planning.

توثيق أسلوب شيكاغو (الطبعة السابعة عشر)

E., Hammam. Trends in the World Demand for Primary Products & Their Impli-cations for the Exports of De-veloping Countries. Cairo: The Institute of National Planning, 1967.

توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)

E., Hammam. Trends in the World Demand for Primary Products & Their Impli-cations for the Exports of De-veloping Countries. The Institute of National Planning, 1967.