1. Hart, P.W. and Connell, D., TAPPI J. 5(4): 23(2006).
2. Natural Gas Price: Henry Hub, LA, Wall Street Journal, Dow Jones & Company, New York, November 1, 1993 - August 1, 2008.
3. Reimer, R. and Kingston, S., Pulp Pap. 77(11): 34(2003).
4. Rantanen, R., Simila, E., and Ahvenlampi, T., Pulp Pap. Canada 106(5): 31(2005).
5. Millsaps, L., “Sulfuric Acid Costs Jump Due to Ethanol Demands,” The Tribune, Ames, IA, USA, February 28, 2008.