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 (Nov. 2015), 1599–1611.