Attarnia, H., and E. Fatai. “Determination of Heavy Metal Pollution in Water, Soil and Plants of Vegetable Gardens in Ardabil”. Journal of Research in Biology, Vol. 7, no. 4, June 2017, pp. 2282-9, https://ojs.jresearchbiology.com/ojs1/index.php/jrb/article/view/445.