1. Ground water is alive and well-It just keeps shifting;Belitz;Ground Water Journal,2001
2. Bureau of Labor Statistics. 2007a. 2006-16 national employment matrix, detailed occupation by industry. http://www.bls.gov/emp/empoils.htm (accessed May 2008).
3. Bureau of Labor Statistics. 2007b. Occupational outlook handbook, 2008-09 edition, environmental scientists and hydrologists. http://www.bls.gov/oco/ocos050.htm (accessed May 2008).
4. Demography as destiny? “Greening,”“graying” & human capital challenges facing environmental management;Durant;Renewable Resources Journal,2003