A. M. Al-Doori, S., & Y. H. Al-Dulaimy, M. (2012). Influence of Zinc Fertilization levels on Growth, Yield and Quality of Some Sunflower Genotypes (Helianthus annuus L.). College of Basic Education Research Journal, 11(4), 741–730. Retrieved from https://stats.uomosul.edu.iq/index.php/berj/article/view/39127