1. Resources
for
the Future, 1616 P Street NW, Washington, DC 20036, United States
2. School
of Forestry and Environmental Studies, Yale University, 195 Prospect
Street, New Haven, Connecticut 06511, United States
3. Department
of Economics, University of Calgary, 2500 University Dr. NW, Calgary, Alberta Canada T2N 1N4
4. Lyndon
B. Johnson School of Public Affairs, University of Texas at Austin, P.O. Box Y, Austin, Texas 78713, United States