5PIGGOT T M. The cataloguer's way through AACR2:from document receipt to document retrieval[M]. London: The Library Association, 1990.
6PEEBLES P Z,Jr. Probability, random variable, and random signal principles[M]. 4th ed. New York:McGraw Hill,2001.
7YUFIN S A. Geoecology and computers: proceedings of the Third International Conference on Advances of Computer Methods in Geotechnical and Geoenvironmental Engineering, Moscow, Russia, February 1-4,2000[C]. Rotterdam: A.A.Balkema, 2000.