Ahmad, D. G., and T. A.-R. A. Gaf. “Lead, Nickel and Copper Concentration and Related Factors in Some Uncooked Vegetables Irrigated by Wastewater”. Advances in BioScience, vol. 3, no. 3, July 2012, pp. 224-30, https://journals.sospublication.co.in/ab/article/view/83.