Voigt, H.-J., Heinkele, T. y Wolter, R. 2004. Characterization of groundwater vulnerability to fulfill requirements of the water framework directive of the European Union. Geofísica Internacional. 43, 4 (oct. 2004), 567–574. DOI:https://doi.org/10.22201/igeof.00167169p.2004.43.4.793.