Najeebullah Kakar, Din Mohammad Kakar, Abdul Salam Khan, and Shuhab D. Khan. “Land Subsidence Caused by Groundwater Exploitation in Quetta Valley, Pakistan”. International Journal of Economic and Environmental Geology, vol. 7, no. 2, July 2016, pp. 10-19, http://econ-environ-geol.org/index.php/ojs/article/view/575.