Hamidullah, S., M. T. Shah, and M. A. Khan. “Identification and Characterization of the Quality of Silica Sand Resources from Munda Gucha, District Mansehra, in Glass Making”. Journal of Himalayan Earth Sciences, vol. 29, no. 1, Nov. 1996, pp. 59-68, http://ojs.uop.edu.pk/jhes/article/view/1486.