Inayat, A., S. R. Khan, and A. Hamid. “Hydrocarbon Composition of Crude Oils from the Oldest Formation of the Punjab, Pakistan”. Biological Sciences - PJSIR, vol. 50, no. 3, June 2007, pp. 173-7, http://v2.pjsir.org/index.php/biological-sciences/article/view/861.