1. Desertification: a world problem;Eckholm;Ambio,1975
2. Air Pollution, Acid Rain, and Future Forests;Postel,1984
3. Environmental Considerations and the Choice of Discount Rate in Developing Countries;Markandya,1988
4. The social rate of discount and the optimal rate of investment;Marglin;Quarterly Journal of Economics,1963
5. Discussion;Samuelson;American Economic Review,1964