Tahir, Ikbal Muhammed Gharib, et al. “Effect of Indoleacetic Acid and Zinc Sulphate Application on Growth and Some Physiological Parameters of Cowpea (Vigna Sinensis Savi) Plants”. Kurdistan Journal of Applied Research, vol. 4, no. 1, June 2019, pp. 15-19, https://doi.org/10.24017/science.2019.1.3.