-Mahmod, A. A., A. J. H . Al-Saidi, & K. A. Saltern. " Effect of Interaction Betw·een Phosphorus and Zink in Some Morphological Features of Two Varieties of Wheat Grown in Gypsum Soil." Ibn AL- Haitham Journal For Pure and Applied Science [Online], 21.3 (2008): 37-55. Web. 22 Nov. 2019