1. Bawden, G.W., Sneed, M., Stork, S.V., Galloway, D.L., 2003. Measuring human-induced land subsidence from space. US Geological Survey Fact Sheet 069–03, 4pp.
2. The Dust Bowl;Bonnifield,1979
3. Basic chronology statistics and assessment;Briffa,1990
4. California's Continuing Drought—1987–1991: A Summary of Impacts and Conditions as of December 1, 1991,1991
5. The California Water Plan Update, 1998, Bulletin 160-98,1998