A. Alwan, Imzahim, et al. “Comparison of Nine Meteorological Drought Indices Over Middle Euphrates Region During Period from 1988 To 2017”. International Journal of Engineering & Technology, vol. 7, no. 4.20, Nov. 2018, pp. 602-7, https://doi.org/10.14419/ijet.v7i4.20.27400.