Silva, M. L. de S., Vitti, G. C., & Trevizam, A. R. (2007). Concentration of heavy metals in grain of plants cultivated in soil with different contamination levels. Pesquisa Agropecuaria Brasileira, 42(4), 527–535. https://doi.org/10.1590/S1678-3921.pab2007.v42.7598