Yaisawarng S and JD Klein (1994). “The Effects of Sulfur-Dioxide Controls on Productivity Change in the United-States Electric-Power Industry.” Review of Economics and Statistics 7: 447-460.
Yaisawarng S and JD Klein (1994). “The Effects of Sulfur-Dioxide Controls on Productivity Change in the United-States Electric-Power Industry.” Review of Economics and Statistics 7: 447-460.