1. Abay, G. and C. Zehnder, 1992, “Road pricing für der Agglomeration Bern”, National City and Transport Research Programme, Zurich.
2. Academie des Sciences, 1990, “L’effet de serre et ses conséquences climatiques”, Paris.
3. Alfsen, K. and S. Glomsr0d, 1992a, “Valuation of Environmental Benefits in Norway”, Central Bureau of Statistics, Oslo.
4. Alfsen, K. and S. Glomsrod, 1992b, “Secondary Benefits of Climate Policies: Some Tentative Calculations”, Internal Note, Central Bureau of Statistics, Oslo.
5. Ansen, F., 1990, “Example City of Visby”, Paper to the Conference on Ecology and Transport, Gothenburg.