1. The Fly Ash Resource Center, http://www.geocities.com/Cape Canaveral/Launchpad/2095/flyash.html (8/5/2003).
2. Energy Information Administration, US Department of Energy, Annual Energy Review, Washington, DC, 1992.
3. Coal Ash Disposal Manual, FP-1257;GAI Consultants,1979
4. American Concrete Pipe Association, http://www.concrete-pipe.org/ (8/5/2003).
5. Doug Mohrman of Concrete Industries Incorporated, 6300 Cornhusker Highway, Lincoln, Nebraska US, March (2003).