Gardea-Torresdey, J.L., Lopez, M.L., Peralta-Videa, J.R. Benitez, T., Parsons J.G. . The Study of PM10 and Heavy Metal Concentrations in Environmental Air Samples of Chihuahua City, Mexico. Ciencia en la Frontera, V, 5058. Determination of the enhancement of lead phytoremediation by Medicago sativa assisted by phytohormones and EDTA. In: Zhu, Y., Lepp, N., Naidu, R. (Eds.), Geochemistry of trace elements: Environmental protection, remediation and human health. Tsinghua University Press pp 698-699. 2007.