1. Alberta Energy and Utilities Board, 2006: Alberta’s Energy Reserves 2006 and Supply/Demand Outlook 2007–2016: Alberta Energy and Utilities Board, Rept. ST09-2007, p. 1-1–8-3; http://www.eub.ca (updated annually).
2. Energy Information Agency, 1979–1980: Bituminous coal and lignite production and mine operations-1977: DOE/EIA-0118(77–78) (published annually).
3. Energy Information Agency, 1981–1993: Coal Production: DOE/EIA-0118(78–92) (published annually).
4. Energy Information Agency, 1997, Table A2. Estimated Recoverable Reserves of Coal by Btu/Sulfur Range, State, and Type of Mining: http://www.eia.doe.gov/cneaf/coal/reserves/appendixa_taba2.html , last accessed February 2007.
5. Energy Information Agency, 1999, U.S. Coal reserves, 1997 update: http://www.eia.doe.gov/cneaf/coal/reserves/front-1.html