Khan, S., M. Ashraf, and S. K. Khan. “Assessment of Drought Occurrences in Zhob District Using Standardized Precipitation Index from 1981-2018”. Journal of Geography and Social Sciences (JGSS), vol. 2, no. 2, Dec. 2020, pp. 110-21, http://jgssjournal.uob.edu.pk/journal/index.php/jgss/article/view/13.