8AL GORE:The Digital Earth:Understanding our Planet in the 21th Century, Given at the California Science Center, Los Angeles, California On January 31,1998.
9彭斌,朱海燕.地理信息系统一原理、方法和应用，科学出版社(北京)，2001
10De Roo A P, Hazelhoff L, Borrough P A: Soil erosion model ling using ANSWER and geographical information systems, Earth Surface Processes and Landforms, 1989(14).
