Gamal, A. A. M. (2016). The econometric analysis of the underground economy in selected Gulf Cooperation Council (GCC) countries: Saudi Arabia, Qatar, The United Arab Emirates, Kuwait and Oman.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Gamal, Awadh Ahmed Mohammed. The Econometric Analysis of the Underground Economy in Selected Gulf Cooperation Council (GCC) Countries: Saudi Arabia, Qatar, The United Arab Emirates, Kuwait and Oman. 2016.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Gamal, Awadh Ahmed Mohammed. The Econometric Analysis of the Underground Economy in Selected Gulf Cooperation Council (GCC) Countries: Saudi Arabia, Qatar, The United Arab Emirates, Kuwait and Oman. 2016.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.