1. The Skeptical Environmentalist, Measuring the Real State of the World;Lomborg,2001
2. U.C. Davis, University of California at Davis, www-geology.ucdavis.edu/-GEL115/115CH11coal.html, printed May 2003
3. Recognizing Pollution's Hazard's;C&EN (Chemical & Engineering News);C&E News,2003
4. Air Pollution Its Origin and Control;Wark,1998
5. King Coal's Weakening Grip on Power;Dunn;World Watch,1999