Fadhel Khalef, Wesan. 2019. “Effect of Interactions Between Nitrogen Fertilizer (urea) and Time Periods on the Growth of Algae Chroococcus Sp.”. University of Thi-Qar Journal of Science 7 (1), 57-61. https://jsci.utq.edu.iq/index.php/main/article/view/250.