S. Shukla, E. A. Hanlon, F. H. Jaber, P. J. Stoffella, T. A. Obreza, and M. Ozores-Hampton, “Groundwater Nitrogen: Behavior in Flatwoods and Gravel Soils Using Organic Amendments for Vegetable Production: CIR 1494/AE400, 8/2006”, EDIS, vol. 2006, no. 15, Sep. 2006.