(1991). Workshop on the costs of limiting fossil fuel CO2 emissions (London, 7 and 8 January 1991), Workshop on the economic analysis of limiting energy related greenhouse gas emissions (Washington, 30 April and 1 May 1991): Summary record. London: United Nations Environment Programme (UNEP).

Workshop On the Costs of Limiting Fossil Fuel CO2 Emissions (London, 7 and 8 January 1991), Workshop On the Economic Analysis of Limiting Energy Related Greenhouse Gas Emissions (Washington, 30 April and 1 May 1991): Summary Record. London: United Nations Environment Programme (UNEP), 1991.

Workshop On the Costs of Limiting Fossil Fuel CO2 Emissions (London, 7 and 8 January 1991), Workshop On the Economic Analysis of Limiting Energy Related Greenhouse Gas Emissions (Washington, 30 April and 1 May 1991): Summary Record. London: United Nations Environment Programme (UNEP), 1991.