1. Al-Abbas, A.H., Barr, R., Hall, J.D., Crane, F.L. and Baumgardner, M.F. (1974) Spectra of normal and nutrient-deficient maize leaves.Agron. J. 66:16–20.
2. Anderson, N.W. and Wendorf, K.A. (1993) Analyzing plant images in the HLS color space. ASAE paper 93-3593. St. Joseph, MI, USA.
3. Bowers, S.A. and Hanks, R.J. (1964) Reflectance of radiant energy from soils.Soil Sci. 100:130–138.
4. Brown, R.B., Anderson, G.W., Proud, B. and Steckler, J.P. (1990) Herbicide application control using GIS weed maps. ASAE paper 90-1061. St. Joseph, MI, USA.
5. Brown, R.B., Steckler, J.P. and Anderson, G.W. (1991) Remote sensing for identification of weeds in no-till corn. ASAE paper 91-1050. St. Joseph, MI, USA.