“Effect of Urea and Humic Acid Fertilization on Some Chemical Physical Properties and Yield of Cow Pea Vigna Unguiculata (L.) Walp”. University of Thi-Qar Journal of Science 3, no. 2 (February 25, 2012): 82–88. Accessed May 4, 2024. https://jsci.utq.edu.iq/index.php/main/article/view/503.