1. Allen, L., T. Bennet, J. H. Lehr, R. J. Petty. 1985. DRASTIC: A Standardized System for Evaluating Ground Water Pollution Potential Using Hydrologic Settings. EPA/600/2–85/018. Robert S. Kerr Environmental Laboratory, USEPA, Ada, OK, 74830.
2. Bekdash, F.A., A. Shirmohammadi, W.L. Magette, T.H. Ifft. 1991. Best management practices (BMP) evaluation using GIS-CREAMS linkage. ASAE Paper No. 91–7516. ASAE, St. Joseph, MI.
3. Bevins, K. J. and I. A. Moore. 1991. Terrain Analysis and Distributed Modeling in Hydrology. John Wiley and Sons Ltd., West Sussex, England.
4. Chen, Z., D.E. Storm, M.D. Smolen, C.T. Haan, M.S. Gregory, G.J. Sabbagh. 1994. Prioritizing non-point source loads for phosphorus with ‘a GRABS-modeling system. Water Resources Bulletin, 30 (4): 589–594.
5. Eidenshink, J.E. 1992. The conterminous United States AVHRR data set. Photogrammetric Engineering and Remote Sensing 58 (6): 809–813.