Khan, F. U., B. Shakila, S. Jehangirb, and M. Ashfaq. “INVESTIGATION OF PB, ZN, MN, NI, CO AND CR IN INSOLUBLE DUSTFALL”. Biological Sciences - PJSIR, vol. 46, no. 2, Apr. 2003, pp. 104-9, https://v2.pjsir.org/index.php/biological-sciences/article/view/1603.