Coal: References
- U.S. Department of Energy, www.doe.gov
- U.S. Department of Energy, Office of Fossil Energy, www.fe.doe.gov
- U.S. Department of Energy, Energy Information Administration, www.eia.doe.gov
- American Coal Foundation, www.teachcoal.org
- Centre for Energy and Economic Development, www.ceednet.org
- Mine-Engineer.com, www.mine-engineer.com
- Tennessee Valley Authority, www.tva.org
- National Mining Association, www.nma.org