1. California Department of Water Resources, 1971: Snow survey measurements through 1970. Bull. No. 129?170, Sacramento, California, 503 pp.
2. Dixon, W. J., 1981:BMDP Statistical Software 1981. Berkeley: University of California Press, 725 pp.
3. Daultrey, S., 1976:Principal Components Analysis. Concepts and Techniques in Modern Geography, No. 8. Norwich: Geo Abstracts Ltd., 51 pp.
4. Granger, O., 1979: Increasing variability in California precipitation.Ann. Assoc. Amer. Geogr. 69, 533?543.
5. Karl, T. R., Koscielny, A. J., Diaz, H. F., 1982: Potential errors in the application of principal component (eigenvector) analysis to geophysical data.J. Appl. Meteor. 21, 1183?1186.