Yousef M.J. Omar, Nasr, M. Radzi bin Abas, Kamal Aziz Ketuly, and Norhayati Mohd. Tahir. 2002. “Chracterization of Solvent-Extractable Hydrocarbons in Airborne and Roadside Soil Particles of Kuala Lumpur, Malaysia”. Malaysian Journal of Science 21 (1&2):171-78. https://mjs.um.edu.my/index.php/MJS/article/view/8606.