Zokaei, M., M. Sepehri, A. Zarei, and F. Jafari. “Determination of the Concentration of Heavy Metals in Medicinal Plants and Assessment of the Risk to Health”. Amazonia Investiga, vol. 7, no. 16, Oct. 2018, pp. 335-43, https://amazoniainvestiga.info/index.php/amazonia/article/view/417.