7McCloy K I, Hall K A. Mapping the density of woody vegetarive cover using Landsat Mss digital data [J]. International Journal of Remote-Sensing, 1991, 12(9): 1877-1885
8Elmore A J, Mustard J F, Manning S J, et al. Quantifying vegetation change in semiarid environments: precision and accuracy of spectral mixture analysis and normalized difference vegetation index [J]. Remote Sensing of Environment, 2000, 73:88-101
9Cihlar J, St Laurent L, Dyer J A. Relation between the normalized vegetation index and ecological variables [J]. Remote Sensing of Environment, 1991, 35: 278-296