8Costanza R, Darge R, Groot R D,et al. The value of the world's ecosystem services and natural capital [J].Nature, 1997,387 : 253-260.
9Sophie M,Thuy L. Biomass quantification of Andean wetland forages using ERS satellite SAR data for optimizing livestock management [J]. Remote Sensing of Environment,2003,84(4) : 477-492.