I. K. AL- Samerria, A. K. Abdullah, and H. S. Rahi. “Role of Potassium on Enzymatic and Non-Enzymatic Antioxidant Activities in Maize Plants Growing under Drought and Hydrogen Peroxide Stresses ”. Journal of Madenat Alelem University College, Vol. 6, no. 1, June 2014, pp. 5-18, http://116.203.176.164/index.php/JMAUC/article/view/190.