7Machin J, Navas A. Land Evaluation and Conservation of Semiarid Agrosystems in Zaragoza using an Expert Evaluation System and GIS[J]. Land Degradation and Rehabilitation, 1995(6):203 -214.
8Turner M G. the Effect of Pattern on Process.Landscape Ecology[J]. Annu.Rev.Eco l. Syst, 1998 (20): 171 - 197.