Ilyas Al-Hamdooni, Dr. “The Effectiveness of Diversification in Reducing Investment Portfolio Risk”. TANMIYAT AL-RAFIDAIN 35, no. 112 (June 1, 2013): 9–35. Accessed September 8, 2025. https://tanmiyat.uomosul.edu.iq/index.php/tanmiyat/article/view/29857.