I.H., Mehdi, and Alasadi M.J.M. 2018. “Effect of Gibberellic Acid and Urea Fertilizer on Some Qualitative and Quantitative Characteristics for Two Celery Cultivars (Apium Graveolens L.)”. Al-Qadisiyah Journal of Pure Science 21 (1), 130 -43. https://journalsc.qu.edu.iq/index.php/JOPS/article/view/880.