Muhammad Zahir. “Analysis and Contextualization of Potential Protohistoric Petroglyphs at the Kalasha Valley of Birir, District Chitral, Khyber Pakhtunkhwa Province, Pakistan”. The Journal of Humanities & Social Sciences, vol. 28, no. 2, Dec. 2020, pp. 35-54, http://ojs.uop.edu.pk/jhss/article/view/375.