A. N. Shah, G. Y.-. shan, S. A. R. Gardezi, W. J.-. fang, and T. Jian-wei, “An Experimental Study on Regulated and Unregulated Pollutants from a Spark Ignition Car Fuelled on Liquefied Petroleum Gas and Gasoline: Pollutants from LPG/Gasoline Cars”, Pakistan Journal of Scientific & Industrial Research, vol. 53, no. 4, pp. 223–229, Jun. 2010.