Haggag, L. F., Abd El-Migeed, M. M. M., Fawzi, M. I. F., Shahin, M. F. M., and Merwad M. A. 2015. “Influence of spraying Zinc Sulphat and Gibbralic Acid on yield and fruit properties of ‘Manzanillo’ Olives”. International Journal of Agricultural Technology 11 (7):1599-1611. https://li04.tci-thaijo.org/index.php/IJAT/article/view/6551.