Cosh, M. H., T. J. Jackson, R. Bindlish, J. Famiglietti, and D. Ryu. 2005. Calibration of an Impedance Probe for Estimation of Surface Soil Water Content Over Large Regions. Journal of Hydrology 311(1-4): 49-58. Refer to the USDA SMEX04 Web site (
http://hydrolab.arsusda.gov/smex04/) for in-depth information on the science mission and goal of the SMEX project.